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C02 ISSUES

jivemonkey

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16 Feb 2022
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worthing
Hi

I have recently switched to RO. I have a trigon 350 planted community tank as attached pic. CO2 diffuser is inline in my external 407 canister. Also have a protein skimmer at the back.

The issue is that since switching to RO my indicator for CO2 in the tank (I have 2 and repalce the liquid monthly on staggered 2 week rotations using different products for each C02 drop checker) is often yellow, but bubble counter now lot lower than pre RO.

I test RO water. Stand it for 24 hours before adding tropic re mineralised using digital scales to be very accurate and test KH, alkalinity GH, PH after dissolving minerals.

I am worried as my tap water tds is around 300 and RO around 150, is the use of RO destabilising pH and can I rely on drop checkers. I am not keen to add further buffers to the water ideally but concerned that the indicators are not accurately reflecting my CO2. If it stays yellow and wipes my fish I suspect I will go back to Malawis. Starting to miss the simplicity and concerned I have bitten off more than I can manage with this project as despite hours weekly, still having problems
 

dw1305

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Hi all,
If it stays yellow and wipes my fish I suspect I will go back to Malawis. Starting to miss the simplicity and concerned I have bitten off more than I can manage
Please don't give up.

I'm not a CO2 user partially because I couldn't forgive myself if I asphyxiated the fish I care for, partially because I'm too mean to buy CO2 and a regulator etc, partially because I'm a <"pretty lazy and sloppy aquarist"> and partially because you don't need it.

If you have a floating plant it has access to 415 ppm CO2 and its growth will never be CO2 limited. Have a look at @Parablennius 's thread <"Floaters"> (and yes, I am still suffering from <"Frogbit envy">, along with <"Ceratopteris and Ceratophyllum "> envy as well, and even worse I've now spammed @Parablennius photo all over UKAPS).
....... Found a sweet spot after a long time. I now front load KNO3 and KH2PO4 at 30% W/C. 1/4 Tsp of each into 60L + 1Tsp MgSO₄ , Tap already has 25/30ppm Calcium. Topped up with a daily squirt of Urea and a splash of trace. Tank TDS hovers around 210 over the week. After W/C indicated Nitrate is 25/30ppm. ......
These plants will grow in hard or soft water, don't need CO2 etc.
dscf2076-jpg.194569

The issue is that since switching to RO my indicator for CO2 in the tank (I have 2 and repalce the liquid monthly on staggered 2 week rotations using different products for each C02 drop checker) is often yellow, but bubble counter now lot lower than pre RO.
I'n going to say that RO shouldn't make any difference, that is the point of having the 4dKH solution in the drop checker. The drop checker has an air gap between tank water and 4 dKH solution, so only CO2 can diffuse across the gap.
I test RO water. Stand it for 24 hours before adding tropic re mineralised using digital scales to be very accurate and test KH, alkalinity GH, PH after dissolving minerals. I am worried as my tap water tds is around 300
I'll be honest I would just add a small amount of tap water as your remineralising agent, you already have a conductivity (TDS) meter and I'd just aim for somewhere near 100 microS, and your water is "remineralised".

If you use a conductivity reading (rather than adding remineralising salts) it doesn't matter if your tap water varies a bit throughout the year. I'm <"pretty slap-dash"> but @Geoffrey Rea is a proper aquarist and <"that is what he is doing">.
is the use of RO destabilising pH and can I rely on drop checkers. I am not keen to add further buffers to the water ideally but concerned that the indicators are not accurately reflecting my CO2
I'm not a <"buffer fan"> (away from a small amount of tap water), they are just a way of <"transferring your money to somebody else">.
is the use of RO destabilising pH
Yes and no, pH is more variable in softer water, but they only place buffering really matters is in the drop checker, where you <"need exactly 4 dKH"> to give you an accurate pH reading and CO2 level.

As soon as some-one starts talking about "pH stability", away from <"Marines or Lake Tanganyika"> you know they don't know what they are talking about, or want to sell you a product, or both.
Also have a protein skimmer at the back.
Does it do anything? The problem with fresh water (compared to marine) is that it is much less dense (because it doesn't have many salts in it) and this means that bubbles are much less effective at removing organic compounds.

cheers Darrel
 
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jivemonkey

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Hi, thanks for this, just home from work and C02 was switched off all day and still greeny hlyellow but pH 7.2. I have two drop checkers with dirrefent solutions and both the same. No idea what's going on at all!!!
 

jivemonkey

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Also alkalinity is 120, KH about 100 and Gh 150. I am only week three of RO switch and do about 30% weekly water change so it's dropped from extremely hard tap water but still no idea why C02 is reading as it is. Help 😳😢
And cheers for tap water suggestion, can easily run through declorinator so may well do exactly that and cut the RO.. Also looking at mixing my own but not sure I want the hassle for same reason I am not keep to re mineralise then ad pH buffer and kh buffer... I feel its fiddling too much and may create more issues
 

xZaiox

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31 Mar 2022
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Maidstone, UK
I am worried as my tap water tds is around 300 and RO around 150, is the use of RO destabilising pH and can I rely on drop checkers. I am not keen to add further buffers to the water ideally but concerned that the indicators are not accurately reflecting my CO2.
Drop checkers are not a panacea, they are to be used as a tool to help you figure out the ideal CO2 level for your tank. Some people get brilliant results with dark-lime drop checkers, others need light-lime, others need yellow. What is important is your plants - are they healthy? Do they show signs of CO2 deficiency? If so, then you have a few options: increase CO2, optimise flow if it's not ideal, or reduce lighting.

Often one of the most effective indicators is livestock; if they hang around the surface to breathe then that's an indicator the CO2 is too high. Some fish that are normally active will become sluggish and inactive. Inverts such as snails and shrimp can be good indicators too, they are sometimes the first responders. If my CO2 goes too high then my shrimp tend to become inactive (normally they would be picking at stuff to eat 24/7, with high CO2 they stand still motionless and hide). I also use fish respiratory rate as an indicator - I find if the levels start pushing it, then fish will start breathing faster and heavier (this sign often occurs before others). If you're ever messing with CO2 levels, then make sure you're around to keep a very close eye on your tank, otherwise you can easily get fish deaths. If levels become too high, then turn the CO2 off temporarily and do a water change.

You can also use pH as a guide. If you have a pH drop of 1.0 then you have a tenfold increase in the CO2 concentration of your tank. This will often result in a 20-30ppm of CO2 range (someone correct me if this figure is wrong). This drop should be measured from your degassed level (take a small cup of water and leave it for 24 hours, then test the pH) - your tank should drop roughly 1.0 or more pH from your degassed reading. This again though, is just a rough figure, 1.0 pH drop will not be sufficient for everyone, but for many it's ideal. My tank needs a fairly large pH drop (I drop from 8.2 degassed to 6.7 with CO2 - my fish and inverts are not bothered by this drop, but start showing stress around 6.6).

Ultimately, I find the easiest way to dial in CO2 is to use all of the above in combination. Once I have found the perfect CO2 for my tank, I find it useful to measure the pH, because it's very easy to reference your tank's current pH level, with the level you recorded to be 'ideal CO2'.

Hope some of this helps - sorry to hear you're becoming disheartened, it can be quite stressful setting up and getting CO2 right. It's typically one of the hardest parts of managing a high tech CO2 injected tank.
 

jivemonkey

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And yes, the protein skimmer removes surface gunk very well and keeps the surface clear, weekly the filter floss is very brown and a little tacky from what it traps. Without this I was getting an issue with surface film built up
 

Hanuman

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The issue is that since switching to RO my indicator for CO2 in the tank (I have 2 and repalce the liquid monthly on staggered 2 week rotations using different products for each C02 drop checker) is often yellow, but bubble counter now lot lower than pre RO.
Let's get this out of the way. It's totally unrelated. Unless you changed your DC solution brand when you switched to RO and you ended up with some solution that is < 4dKH, the solution in the DC has always been 4dKH. This means the use of RO or TAP doesn't change a thing to what your DC says.

just home from work and C02 was switched off all day and still greeny hlyellow
That is not normal. Perhaps your DC solution is screwed or your CO2 distribution and gas exchange is poor. After a full day without CO2, your DC solution should be dark green or even blue if you have a lot of surface agitation.

Also alkalinity is 120, KH about 100 and Gh 150.
Are you sure your KH is at 100. I find that very suspect considering you are using RO. It should read very low KH.

What you are experiencing is EXACTLY why I never rely on a DC to know if my CO2 is ok. Depending where you place your DC, its reading will vary considerably specially if you are using an inline diffuser where you will have lots of bubbles. That's because depending whether the flow of bubbles is in the path of the DC the solution in the DC will change colors at different rates. Since you are now using RO I would advise the 1 PH drop method as described above. Tweak it from there more or less.

Perhaps providing a picture of your tank with everything in place would help better assess what's going on.
 

dw1305

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Hi all,
Let's get this out of the way. It's totally unrelated. Unless you changed your DC solution brand when you switched to RO and you ended up with some solution that is < 4dKH, the solution in the DC has always been 4dKH. This means the use of RO or TAP doesn't change a thing to what your DC says.
That one.

cheers Darrel
 

jivemonkey

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Let's get this out of the way. It's totally unrelated. Unless you changed your DC solution brand when you switched to RO and you ended up with some solution that is < 4dKH, the solution in the DC has always been 4dKH. This means the use of RO or TAP doesn't change a thing to what your DC says.


That is not normal. Perhaps your DC solution is screwed or your CO2 distribution and gas exchange is poor. After a full day without CO2, your DC solution should be dark green or even blue if you have a lot of surface agitation.


Are you sure your KH is at 100. I find that very suspect considering you are using RO. It should read very low KH.

What you are experiencing is EXACTLY why I never rely on a DC to know if my CO2 is ok. Depending where you place your DC, its reading will vary considerably specially if you are using an inline diffuser where you will have lots of bubbles. That's because depending whether the flow of bubbles is in the path of the DC the solution in the DC will change colors at different rates. Since you are now using RO I would advise the 1 PH drop method as described above. Tweak it from there more or less.

Perhaps providing a picture of your tank with everything in place would help better assess what's going on.
 

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Hanuman

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4 Jan 2019
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I don't see much surface agitation going on there. I know it's a still photo but I don't see many ripples on the surface. Is there a way for you to increase surface agitation and place the DC at different locations. This will give you an idea of the water flow and CO2 distribution.
Basically the idea is you need to bring the top layers of water (highly oxygenated) to the bottom and the bottom layers of water to the top. This enables you to properly oxygenate the water column and to avoid excessive CO2 concentration in the lower layers.
 
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