# How to improve my CO2 graph



## jsiegmund (17 Mar 2016)

I'm looking for some tips on what I can do to improve my CO2 graph. I've read quite some threads on the subject and the common goal seems to be to acheive a 1 point drop before lights on. Now since yesterday I have an automated set-up reading and storing my temperature and pH values every 30 seconds. This gives me a pretty decent idea of what's going on, see below:





Now you also see where the trouble is. CO2 came on at 11 (I already moved that moment to 10) at which point the pH starts to drop. But it keeps on doing so throughout the day and I never even get to that full point drop. 

So now I wonder what I should do to improve this. Obviously I can open the tap a bit more, but I'm already inserting quite a lot of gas. My tank is a 240 liter, I'm running an FX5 for filter and have an AM1000 outside reactor for dissolving. I've removed the bioballs but kept a bit of foam in the reactor to trap the smaler bubbles, otherwise they get sucked out. I always have some bubbles going round in the tank nevertheless, which makes me think that inserting more gas would only mean more gets blown in the tank and escapes via the surface. 

I also thought about aiming my spraybar a bit more downwards to mimize surface agitation. I do get some film over time, but have solved that already using a skimmer which turns on for two hours during the night. 

Reason for this all is some BBA growth and some plants not performing at their best, I just know for sure there's room for improvement! Good thing about my app is that I can now easily try things and see the outcome the next day right on my phone


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## GTL_UK (17 Mar 2016)

What do you use for these graphs? 

Thanks


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## jsiegmund (17 Mar 2016)

GTL_UK said:


> What do you use for these graphs?
> 
> Thanks


My own developed app  still in development, who's interested can take a look at my blog for a how-to series (blog.repsaj.nl, developer skills required). Maybe in due time I'll create a service so everyone can hook-up 

Sent from my ONE A2003 using Tapatalk


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## Martin in Holland (18 Mar 2016)

I can't seem to make head or tail out of this (but this could be just me, should have payed more attention in school ). It doesn't say when the lights come on what time your CO2 turns on and off or even what time of day it is...or does 00 mean that the lights are on and 18 the lights turn off...KH level would also be help full.


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## jsiegmund (18 Mar 2016)

Sorry about that, that's the "in development" part I guess. Makes sense to me but maybe not to others.

- CO2 on @ 11:00 
- Lights on @ 12:00 (30 min ramp)
- CO2 off @ 20:00
- Lights off @ 20:30 (30 min ramp)

The horizontal axis "Hours" is a 24 hour range (so 09 = 09:00, 15 = 15:00, etc.). So the graph displays a full day, only the last 3 hours are missing because I took a screenshot before that time. Doesn't really matter since at that time lights are off again any way. Need to measure KH again, but should be around 7.


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## Manu (18 Mar 2016)

Hello jsiegmund,

Looking at your graph, you only had a 0.12 point ph drop (from 7.17 to 7.05) by the time the lights went on...I know you changed the time for the co2 to come on at 10am, but this will still only give you 0.24 point of ph drop. Obviously, something is not right as if the ph dropping rate would be constant it would then take you about 8 hours to reach the one point ph drop... Are you able to count how many bubbles are coming out of the tube inside the reactor? Count per minute, those are big bubbles...
Also, one interesting test is to take some water from your tank in a glass, leave it for 24 hours to degas and measure its ph. I read some people are using this value for the desired ph drop...
I am using the same reactor for a 200l tank and what works well for me is having an inline atomiser on the return hose after the reactor. I have a manifold so I can adjust each bubble rates (reactor and atomiser) to get the best result without having too much fizz in the water. I hate fizzy water and that's why I bought the AM1000 but I was not able to achieve the ph drop with only using the AM1000, or I would get a massive build up of gas in the reactor.
Also, I have the co2 coming on a long time before lights on, I think four hours or more. I don't know if this should be the case but again it works with my set up (your tank is even bigger...) and for the moment it seems to be the best solution. And of course, it switches off early too as there is always about 2.5cm of gas build up in the top of the reactor in the last hours of lights on...
Of course, check your flow too. Your filter turn over is just under your tank size and the reactor even with the bioballs removed will reduce its flow...

I hope this is helpful and that you sort this out soon 

Cheers,
Manu

ps: add a non return valve after the bleeding valve of the AM1000... it tends to leak...


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## jsiegmund (18 Mar 2016)

Thanks for your reaction Manu. I would suspect my pH to level off at about 7.5 as that is also what my tap water is (and I do my water changes primarily with tap water). I have an Akadama soil, but the pH lowering qualities of that are probably gone by now (last for a year or so I believe). Which means I do get close to a 1 point drop at about 6.5, but I'll try a proper measurement just to be sure. 

I have a bubble counter before the reactor, but that one already goes way too fast to read. Inside the reactor I've got an airstone attached to the hose in an attempt to break up the bubbles a bit. I have the same problem you have; inserting too much gas will start a build-up inside of the reactor which doesn't improve the pH anymore. An inline diffusor isn't going to work as I've modded the reactor to have much bigger connectors, attached using 25/18 Eheim hose in order not to hinder flow too much. If I were to run an inline diffusor (which don't come at that size I believe), I'd be forced to reduce flow again reducing to a smaller size hose. I did consider putting a diffusor inside of the reactor itself, but that too will probably hinder flow a lot (the airstone is relatively small and kind of does the same). Aqua Medic should sell something to solve this, I'd buy it  I never been able to get 0 bubbles inside of the tank which I also prefer.

I could move the CO2 window so it comes on way earlier and shut it down earlier too, 4 hours still won't get me a 1 point drop though. I guess in larger volume tanks you also have more buffer so it takes quite a bit longer before all the gas is vented during the night? Luckily I have my graphs to tell me more about that  

As for the bleeding valve: never had any issue there but I'll make sure to do so just to be sure.


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## EdwinK (18 Mar 2016)

As Martin in China asked - what is your kH reading?


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## EnderUK (18 Mar 2016)

I gave up on the AM1000 as I was having similar issues which come to the fact I wasn't getting enough flow through it with my 1000lph filter. CO2 just wasn't dissolving fast enough, leaving the AM1000 about half full with CO2 by lights off. If this is the case you're having then I would suggest getting a larger filter or a dedicated pump to run it. You could try running the CO2 much earlier 3-4 hours before lights on and turn it off 2 hours before lights off.


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## Manuel Arias (18 Mar 2016)

Hi jsiegmund,

Well, the classical problem of CO2-KH equillibrium. With kH= 7 you have buffered you water so essentially, the CO2 being disolved causes a drop in the pH which is compensated by carbonates taking protons, so meanwhile your kH keeps at that value and your CO2 injection at your current status, you will never get that drop, which, by the way, it means nothing, as the drop will be fully different depending on the kH, and not linked at all with your actual levels of CO2 and HCO3- in your tank. In other words: the fact that you do not see an (apparent) significant change in the pH does not mean that you are not getting the right levels:



 

In fact, your pH is dropping from about 7.15 to 6.58 (0.57 units). Note that pH scale is logarithmic so essentially, you are incrementing the concentration of protons in 3.7 times due to the CO2 injection. If you look at the table, the level of saturation of CO2 is changing with your current drop of pH and considering your kH, from 17 ppm to around 53 ppm, so there is a huge impact of your CO2 injection in your system. In fact, it is more or less agreed that about 30-40 mg/l of CO2 is more than enough. But then, we are talking considering that your kH keeps fixed during the day, which does not. Your kH will also drop during the day as response to the generation of protons by your CO2 injection, which explains why your pH does not reflect such big impact as you expect. If you want to know really what is going on, a kH check before CO2 injection starts, and just after it stops, will give you the range of kH drop that you have plus your variations of pH, so you can guess what actual levels of CO2 you get. The colours of these charts are not decorative. The blue region represents the conditions in which a drop checker remains blue, the green when the liquid gest green, and the yellow when gets yellow. A rule of the thumb, if what you are looking is saturating of CO2 is to induce a CO2 injection able to push your drop checker to start to be yellowish.

In conclussion, I do not see why you need to increase your proton concentration ten times...currently you have more CO2 than required for your plants. If you think that your pH is too high, then just reduce your kH slowly until you achieve your wished pH. Note that dropping kH will mean also that your current CO2 injection will cause a bigger drop of the pH.

Hope this help!

Cheers,

Manuel


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## jsiegmund (18 Mar 2016)

@EdwinK that was already in my 2nd post  It's about 7 before lights on (see below).

@EnderUK so what did you swap the AM1000 for? An in-tank diffusor? I can't really imagine a dedicated filter or pump would solve anything. The throughput I have now is already pretty high. If you get a chamber of gas, I think the problem might not the throughput but the contact area of gas of water. A chamber of gas has a much smaller contact surface than all the same volume of gas in the form of tiny bubbles. That was also my reasoning behind putting in an airstone on the end of the CO2 line. 

@Manuel Arias thans a lot for the explanation. I just measured kH as CO2 has turned off 15 mins ago and it now reads 5. I'll do a double check tomorrow but I expect the value before CO2 to be 7, which means the range would be 5 - 7. Could you help me figure out what that means for the CO2 availability for my plants? 

If I read your story correctly, then in fact I might even have too much CO2. So what could then be the cause for what I identified as CO2 related issues? BBA, some green spot and not all plants are growing optimally. Especially my staurogyne repens and alternanthera reineckii mini could do better. They're not melting, but they don't look completely healthy either (I'll try to get some new pics this weekend). I read that it's good to have a stable CO2 (and kH?) reading throughout the period the lights are on. So when I inject less CO2 and begin doing that a bit earlier, I might get to a proper balance on the point the lights go on? Would shifting the CO2 window help at all in your opinion?


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## jsiegmund (19 Mar 2016)

Update: strange, I did another kH check just now and that one also read 5. So that would indicate the kH doesn't change at all during the day. I did change the times so it now comes on @ 09:00 (3 hours before lights) and shuts off @ 18:00 (2,5 hours before lights off). Let's see what happens next...


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## Manuel Arias (19 Mar 2016)

Hi jsiegmund,

Sorry, I did not mention that the kH "consume" does not recover itself unless you have something in the tank releasing such kH. Many typical rocks for aquariums are really varieties of limestone, so they release carbonates to water when the pH drops from certain level (usually under 8). The system can be represented in a simplistic way as follows:



 

This equation shows the mentioned equilibria. The CO2 dissolved in water becomes in a weak acid that releases protons to water, dropping the pH. In a second stage, if the pH is high enough, a second proton is released becoming into carbonate. As you see, the equilibria is strongly dependent of pH, as it is the measure of protons in water (well, formally speaking, the proportion of protons vs hydroxles). 
When the pH is lower than a certain threshold, the carbonates tend to associate to protons, increasing the concentration of bicarbonates and also the pH, as some protons disappear from the water. This is a tampon effect, as the income of carbon dioxide has the opposite effect. So, essentially, the drop of pH caused by the dissolution of CO2 into water is compensated with a reduction of the carbonates into water.

The solubility of the carbonates depends also in the pH, so essentially, when the pH is low the carbonates tend to disappear from water (progressively reducing kH) but if there are some precipitated carbonates (like limestone) the rocks starts to dissolve, incrementing the kH.

So, essentially, some rocks can help to keep kH at some levels, but I will not trust that too much, as it is difficult to say how much rock is good. Too much rock can produce very high kH so you never get CO2 at right levels. Too few will have not the necessary kH. Because of this, many people in the hobby just keep very low kH levels so they do not have to controlling that.

But going to your explanation, what is happening in your tank then is the CO2 injection is using the carbonates to compensate the drop in kH. It is then not surprising that the parameter reduces with time, which also impact into your levels of dissolved CO2, as derived from the table. For instance, with a pH of 6.6 and kH of 5, you have theoretically speaking about 48 mg/l of CO2, which is fine for your plants. Note that these tables are computed assuming that only parameter affecting pH is inorganic carbon equilibrium, which is not true, but quite close to reality. 

CO2 levels of 30-40 ppm have been reported as good ones for plants. Higher levels, meanwhile pH does not drop too much are not harmful for plants, so we talk about a minimum level. Lower levels will also produce growth in plants for sure, but then light and nutrients must be tuned to these lower levels of CO2 in water to avoid algae, and plants will grow also slower. There is nothing wrong with that (it is in fact my approach), but some people like to trim stem plants every week!  Only real problem with high concentrations of CO2 is that you could gas your fishes, but I would say 48 ppm is still within the range of safety.

Regarding your plants, problems could be many. Could you please upload some photos of your plants as well as the technical description of your setup?

Hope this help.

Cheers,

Manuel


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## jsiegmund (19 Mar 2016)

Great stuff @Manuel Arias ! I must admit that I might not understand everything 100%, but it does help a lot to have an idea what's going on. I understand the need for pictures, so here are some. Quality isn't the best but I it should do.

Some holes in leaves, not sure whether the fish are culprit to these:




Alternanthera reineckii mini, one of the plants I know can do better. Some leaves have algea and other have holes in them.




As mentioned, the staurogyne repens. Looks ok but grows high where I want it to carpet (more about this below)




BBA on some Lilaeopsis Novea-Zelandiae




And lastly an overview on which you don't see the issues real good. As you can see there's also a lot of green which does do fine  




The technical set-up:
* Fluval FX5 filter
* AM1000 CO2 reactor linked to a dual stage regulator on a 2kg cilinder. Lasts me about a quarter of a year.
* Lighting is locally branded SMD LED, both white as well as RGB which I use to add some color tones (the white ones are a bit blueish).
* Lights run from noon till about 20:30, both starting and ending with a 30 min ramp
* As said I've now shifted the CO2 window to 09:00 - 18:00.
* Dosing EI using macro mix + PO4 and NO3 seperately. Dosing that daily at night using a dosing pump.
* Also dosing some Excel daily to keep control over BBA
* Weekly water refresh of 50% using tap water.

Water readings for today: kH 5, gH 8, NO3 20, PO4 0.5. PO4 is always a bit low cause it probably gets bound to the soil. No matter how much I put in it's never much higher than this. Shouldn't matter in my opinion as there's always something available for the plants?

That about it I think. Now I know that some of the above issues (mainly the staurogyne growing tall) might lead to think that I have too little lighting. I have plenty of room left to go brighter but the problem is that that immediately worsens the BBA trouble. BBA is commonly associated with CO2 problems, so that's why I was looking in that area. I think I might get the staurogyne to carpet more when I bring some more light, but I first want to deal with the issue in balance before I start doing that.


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## Manuel Arias (19 Mar 2016)

Hi jsiegmund,

Many algae problems are related to low CO2 levels, but there are further reasons than this one to have algae. You have several types of algae, so it is clear that is not a single thing but probably a combination of parameters. In my point of view probably due to low PO4 and long hours of light.

Respect to the light, I would increase intensity to help your Staurogyne repens to be smaller and also to the other plants to grow better, but I would reduce the photoperiod, maybe a couple of hours or even three hours for a start, to be then 5.5-6.5 hours instead of 8.5 hours as you have now. This should avoid you the BBA trouble when you increase the light (by reducing the time you have the lights on). Note that important point for the plants is the right dosage of the right photons during a given time, so increasing intensity and reducing time will provide better quality of lihht for the plants, which will allow them to make better use of the nutrients (i.e. ramping down the algae in the way).
Respect to CO2 levels, they seem right as they are now. At start, looking at the photos, I thought that your mix of water was not being good enough, causing the problems, but your filter and spray bar should grant you the water flow you need. BBA is not only due to low CO2 levels...it is also associated to dissolved organic matter, which is usually also larger in areas of the tank with less water flow.
Regarding the phosphates, I am intrigued. It is curious your levels of PO4 stick to a specific value, as that makes not much sense. What kind of soil are you using? Are you adding iron at the same time than phosphates? I think that can have something to say in the problem. You are right that you do not need to have big quantity of it, but if your phosphate is disappearing means that is being consumed or is reacting with something else, so yeah, try to increase it but with an eye of the concentration you get in the tank. If it is the soil, it will eventually saturate, so the sooner that happens the sooner you can keep it at the right levels. If it is the plants, then they need more, and if something else, then it needs to be fixed. 
Regarding the CO2/kH/pH, best thing is to use a drop checker, as it is the easiest way to monitor it, looking at kH from time to time to ensure that is not dropping too much so pH is more stable.

Of course, these are just guidelines. Try to apply any change in a progressive way, and see how the plants behave. Usually that is the best way to track the impact of our actions.

Cheers,

Manuel


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## jsiegmund (20 Mar 2016)

Ok, so I've changed the photoperiod to 14:30 - 20:00 to give this a try. That makes 5.5 hours to start with. I've also boosted the intensity for this period. According I've adapted the CO2 to now go on @ 11:30 (3 hours prior) and shut off @ 18:00 (two hours prior). I'll monitor the graphs to see what that does.

As for the PO4, that intrigues me too. I am using an Akadama soil which indeed is known to bind PO4 in the beginning, but I've got that for two years now so it shouldn't be doing that any more. Apart from that I've got no idea where it could be going. The dosing is done on alternate days, so on one day I dose PO4 and NO3 and on the other day I dose the macro's, both at midnight. The Excel I dose extra is added in the morning before the photoperiod (ah, should shift that too). Thanks again for the help and suggestions, will keep you updated on what happens next.


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## Manuel Arias (20 Mar 2016)

OK, brilliant. As said, best thing is to look how it evolves with these changes. If you see things improving, perfect. If you feel it is not working, just go back to the original line and then maybe try another thing. We will see.


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## jsiegmund (21 Mar 2016)

Yes, we'll see indeed  

In the meantime I'd like to ask some more questions if that's ok. You mention that reducing the photoperiod will help to battle the BBA problem whilst increasing intensity will help the plants. The latter I get, but why does a shorter photoperiod help with BBA? Why are we hurting BBA (or at least slowing it down?) by reducing the photoperiod whilst in the same time it helps the plants?

I also wonder about the kH levels. So I now understand why it drops and doesn't regenerate again as I previously expected. I suspect I now also know why some of my helena snails have a battered house, it's probably because my rather high CO2 levels are consuming the carbonate in their houses, right? If so, that's too bad for the snails but I wonder about the process in general. You mention some rocks release carbonates in the water. In my first set-up I had that very problem: both stones (seiryu) as well as the soil I used were messing with the water parameters which too was causing CO2 related issues. That was one of the reasons I switched to an Akadama soil and dragon stone, neither leach carbonates. The Akadama in it's first year would take down the kH to near 0 like some aquasoils do too. It's lost that property now it seems. 

What are the benefits of having a stable kH? I was taught that in any tank, you want things to be as stable as possible so the plants (and fish) don't have to continuously adapt to changing parameters. If I want to stabilize the kH, it would be better to have some source of carbonates if I understand you correctly. Would that help in any way? Reason i ask is that I've kept a small bag of the old soil so I could place that in the tank or filter. That would even be controllable in the amount of carbonates it releases as I can add more soil or remove some when needed. The tap water I use has a kH of 9, so it can drop some points during the week to the point where I refresh the water again. I have an RO unit but at the moment only use it for creating stock solution and such, I don't want to waste too much water when I don't need to


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## Manuel Arias (23 Mar 2016)

jsiegmund said:


> In the meantime I'd like to ask some more questions if that's ok.



Of course! No problem at all. 



jsiegmund said:


> You mention that reducing the photoperiod will help to battle the BBA problem whilst increasing intensity will help the plants. The latter I get, but why does a shorter photoperiod help with BBA? Why are we hurting BBA (or at least slowing it down?) by reducing the photoperiod whilst in the same time it helps the plants?



Fair question. This goes to the relative efficiency in which plants and algae use the different resources. As general rule, algae are better adapted to take advantage the low levels of CO2, for example, so when these levels are low, the plants are not having a good perform with the photosynthesis, which means they leave the terrain for algae, who can grow with lower concentration of CO2 and then take advantage of the nutrients the plants cannot control. However, under the right conditions, plants control better the environment. With the light a similar phenomena happens. A low PAR is associated to algae, because the plants are not so efficient. Algae behave as opportunist in terms of ecology, which means that they will always use the resources found in excess when others are missing. Aquatic plants, however, are specialists, so they perform better when the conditions are favoring them. 

In the case I mentioned, having a low PAR for long hours will help algae. Plants cannot perform well with a low PAR because they will not getting enough energy for they photosynthetic processes. However, algae can use this reduced light, and as plants are not consuming nutrients, they have a based stone to build up. By increasing the intensity, you provide the right PAR to the plants, and under these conditions, plants will perform better and will use more the nutrients in water, which leaves no room for the algae. If the light is intense, plants do not need to get closer. The reason why your Staurogyne was growing tall is because the plant is trying to go closer to light to access to a better PAR. However, if the PAR is correct, the plant do not need this, so use its growth to cover the maximum horizontal surface as possible, as it is a better strategy for the plant if the light levels are good. However, as said before, algae will use what is in excess, so if you keep an intense light for long time and there are enough nutrients in water, then other types of algae will appear as these conditions can help them. In the case of BBA, it needs certain levels of light. I noticed that in my tanks never appear in areas that are dark. This is why when you were increasing your intensity, your BBA were happier. However, both plants and algae work in bases to the total amount of PAR received during a period of time. In other words: It is not only the PAR but also the time which gives the right dosage. But this is also on top of the fact that they need also a minimum intensity to work fine. With a low PAR for long hours what happens is that your intensity is not enough for the plants, but the accumulated radiation is enough for BBA, so essentially they have options to grow and compete with the plants.

In general, to ensure you beat algae, there are three rules that usually work: a) Reduce the amount of organic matter in decomposition (i.e. cleaning dead leaves, filter media, remove scum building up in the areas with low water flow); b) Reduce the photo-period to ensure algae cannot receive the PAR and dosage of radiation they need. Most plants survive some periods of time with no light at all, but many algae are not able to do so; c) Balance the nutrients (i.e. ensuring no nutrient is in deficiency) and reduce its dosage so we avoid to have any excess favoring opportunists (the commonly advised water changes goes in this direction).



jsiegmund said:


> I suspect I now also know why some of my helena snails have a battered house, it's probably because my rather high CO2 levels are consuming the carbonate in their houses, right?



Absolutely correct. The shells of molluscs are made of precipitated calcium carbonate and chitin (a kind of organic molecule used by many inverts to create hard structures). The CaCO3 is only stable in water if pH is about 7.8 or higher. This is due precisely to the equilibrium I mentioned above. When there are many protons in water, they will tend to bind to carbonates to produce bicarbonates, which are highly soluble in water. The calcium is also then released to the water. When you inject CO2 and your pH drops, then the shells of your snails will suffer the same acidic attack than carbonated rocks, so yes, that is why the appear battered. In fact, most of molluscs and crustaceans only appear in waters with high pHs, as otherwise they have problems to create/preserve their shells, which makes them more vulnerable to predators and diseases.



jsiegmund said:


> I was taught that in any tank, you want things to be as stable as possible so the plants (and fish) don't have to continuously adapt to changing parameters



Yes, totally right. You will find people telling that the aquatic organisms live in environments with a high variability of parameters, but that is quite false. Many of the species are very specialized to specific conditions (not all, of course), but despite of that, all species benefit of stable conditions. Jumping parameters just cause them problems and stress, which translates to a lack of growth and/or diseases.



jsiegmund said:


> What are the benefits of having a stable kH?



The main advantages are two: a) It buffers the water and stabilizes the pH so help a lot in the goal to keep a stable environment. pH jumps are cause of stress, and, opposite as said by some, natural waters keep a quite constant pH, unless we talk of some specific lakes which can have some annual cycle related to high productivity. Whwn we talk of rivers of springs, water parameters quite stable. So stable that some species of fishes like salmons are able to "smell" the water of the rivers by the signature they leave in the sea and go back to the place they were born. They could not do so if the water of these rivers were substantially changing; b) It helps to get the right levels of dissolved CO2 without having to drop too much the pH. Plants are more tolerant to low pH (not all of them) but even so, if the pH drops too much, they will be harmed by an acidic water. A kH between 3 and 8 is considered still very soft water but helps to avoid the pH having to drop too much to get the right CO2 levels.



jsiegmund said:


> If I want to stabilize the kH, it would be better to have some source of carbonates if I understand you correctly. Would that help in any way? Reason i ask is that I've kept a small bag of the old soil so I could place that in the tank or filter. That would even be controllable in the amount of carbonates it releases as I can add more soil or remove some when needed. The tap water I use has a kH of 9, so it can drop some points during the week to the point where I refresh the water again.



This is very difficult to achieve, and that is why many hobbyist just decide not to bother with kH, which eventually drops to zero if they do not have any source of carbonates in the tank, with a high risk of killing the fishes. Or maybe they have carbonates and happens the opposite if they do not compensate the increase of carbonates with water changes. So here, in your case, you had a very bad combination. kH of 9 is fine (a bit high for my taste but still good) in tap water. If you do not have any source of carbonates, the kH will drop due to CO2 injection, and will recover again when you change the water. However, depending of the drop of kH between water changes you suffer, and the amount of water you change, the recovery has some limits. For instance, in an extreme case, if your kH drops to zero between water changes and you change 50% of the water in your tank, after the maintenance you get a kH of 4.5, which will disappear sooner than when you started with 9, so your tank will spend more time at kH close to zero. On the other hand, if you have a kH of 9 but you have carbonated rocks, it could happen that you kH not only does not drop but that increases within the time, even with water changes: You start with 9 and between water changes increases up to 12. When you change 50%, after maintenance you kH goes to 10.5, higher than your starting kH of 9, so eventually increases to levels that are totally bad for your tank.

Finding the balance with the hardscape can be difficult, and the impact of rocks as seiryu depends on the amount you have. These rocks, however, are not so harmful as some sands, as the impact is also related to the total amount of surface of carbonated rocks in contact with water, which much much large in sands than in big rocks. Your idea of using some amounts of that sands to try to balance kH can help. Maybe best option is to introduce it in a net that you keep hide in the tank outside of sight or in the filter. You can play with the amount of that sand in the bag until you get a more stable kH. Note that, however, that kH will change anyway with the water changes, unless you aim to get it stable at the kH of your tap water.

In the case of my tank, kH slowly grows, but I compensate it from time to time by increasing CO2 levels and water changes.



jsiegmund said:


> The Akadama in it's first year would take down the kH to near 0 like some aquasoils do too. It's lost that property now it seems.



Yes, this is normal. Akadama and aquasoils make more acid the water by ion exchange, which is related to the composition of the clays that are their main mineral. They release protons to water usually as exchange of potassium. Eventually these exchange happens with most of the possible protons, so at the end the effect dissappears and they stop dropping the pH.

Hope this help.

Cheers,

Manuel


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## jsiegmund (31 Mar 2016)

Ok here's a quick update. First of all thanks again for all of the answers, very much appreciated! 

First the good news: no real big outbreak of BBA (yet)! Which doesn't mean it has disappeared or stopped growing (unfortunately), but there hasn't been a real big boom which I kind of was expecting. This weekend I cleaned out my filter and replaced some of the stock solutions which had a bit of fungus on them. I placed a mesh bag of the old soil in the back of my tank as a temporary source of carbonates. Not sure how I'm going to find out whether this is working or not: measure kH before the next water change? Yesterday I stopped my filter for a while and spot treated the BBA using Excel. Plants seem to be doing ok; they're not getting worse but there's also little noticeable improvement yet. So for now I'm not yet sure whether we're onto a solution here or not. Suppose there's not much change in the coming weeks either, what could be other things to try?


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## jsiegmund (7 Apr 2016)

Another quick update. I've increased the lighting a bit more by running my normal T5's which I still have in the tanks hood for 4 hours during the time the LED lighting is on. Reasoning behind this is that  I'm not sure whether the LED's (SMD 5050) are sufficient to have a good reach / spectrum. In order to resolve this more permanently I've ordered new 8520 chipped strips which should give me way more lumen. Ordered both normal white and warm white to see whether I can also improve the color temperature a bit, I'm still not pleased with how things look now. 

The T5's have been running for three days now. The only noticeable difference is that I seem to have more surface film than before. I always had a bit of film so I have an Eheim skimmer running during the night. I'll increase the duration a bit to see whether that helps with the film. Is this film being caused by increased bacterial activity due to higher lighting? 

Plants look ok. Gave the moss a good trimming last weekend and it's already bouncing back in bright green. For the struggling plants, no real improvement there (yet). Got some urea from a buddy of mine, will see whether dosing a bit of that maybe gives things a kickstart. Any additional tips are very welcome


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## jsiegmund (18 Apr 2016)

Finally! Time for an update with pictures! 






That's the tank as it sits now, nice and healthy! And here's one with the additional T5 running:




The camera makes the difference more dramatic than it is in real life, but still; it's considerably more lumens hitting the plants. I've got new LED strips lying waiting for the connectors to arrive from China. Those should be brighter and I've ordered both 'normal' white and warm white to see the difference it makes to the looks of the tank.

As for the plants, things definitely seem to be improving:



I've moved the staurogyne to a place near the front, it seems to like that.




Grass (Lilaeopsis Novea-Zelandiae) is improving, not algea free yet.




Marsilea crenata looking good



 Alternanthera Reineckii also doing a lot better. It stays fragile though, sometimes I spot a floater.




Some pearling on the weeping moss. Did a radical trim last week and it's already grown back amazingly. But look closely and you'll spot some BBA in this pic.

There's been a few things I've done so far:

- Shorter lighting period
- Adding the T5 for increased intensity
- Upped the dose of PO4
- Added the dosing of Urea

So I cannot really tell which of these did the trick, or maybe it's the combination of everything of course. My latest water parameters were: kH 5, gH 10, PO4 0.5 and NO3 20. Yes, the PO4 is still 0.5 even though I'm dosing more. I'm not convinced that this means the plants are using more, cause in the past I could dose pretty much any amount, readings would always say 0.5 :S

The BBA isn't completely gone yet, but I've forced it back onto the hardscape as most plants seem to be clean now. I've trimmed away some leaves which still had it but the new growth seems to be doing better. I also still have some green spot algea, mostly on the glass (BBA there as well) and on the Lobelia cardinalia. I'm going to wait untill I have the new lights installed to see what happens. For now I'm pleased with the results already as there definitely seems to be improvement! Thanks again for all the help, especially @Manuel Arias !


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