# Am I overdosing CO2 to add shrimps/fish?



## mede (15 Sep 2014)

I'm staring up a new tank for four weeks right now and I have reached the point where I want to add some Amano shrimps and Otocinclus. I have seen the first signs of brown algea, but that's probably related to the new setup.

I have created a pH profile during one day with a calibrated HANA pH pen and the profile looks like the list below.

I am afraid that the pH drop from 8.2 to 6.3 is too much for the Amano shrimps and fish (Rasbora). Every day a pH swing of almost two points. I don't want to use the animals as test material to see if it's OK to add them to the tank. What is your opinion?

I also dose 2.5ml EasyCarbo every day on a 53 liter tank and following EI-method. KH = 8.

10:40 - pH 8.2
12:20 pH 8.2

12:30 CO2 SWITCH ON
12:32 - pH 8.1
12:36 - pH 7.7
13:40 - pH 6.6
14:06 - pH 6.5

15:00 LIGHTS SWITCH ON
15:46 - pH 6.3
16:12 - pH 6.3
17:06 - pH 6.3
18:10 - pH 6.4
18:37 - pH 6.4
19:22 - pH 6.3/6.4 (display switching between those two values)
19:44 - pH 6.3/6.4 (display switching between those two values)
19:58 - pH 6.3/6.4 (display switching between those two values)

20:00 CO2 SWITCH OFF
20:10 - pH 6.4
20:30 - pH 6.5
20:44 - pH 6.6
20:52 - pH 6.6
21:00 LIGHTS SWITCH OFF


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## EdwinK (15 Sep 2014)

Please check this table - http://s171.photobucket.com/user/plantbrain/media/Aquatic plants/CO2_Graph_zps9c124ef0.gif.html
Your CO2 level shoud be in 30-40 ppm range. Anyway, I would recommend to lower it to 20 ppm and then introduce your fish and invertebrates. Later on you could start adding more CO2 and inspect your fauna's reaction.


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## mede (15 Sep 2014)

There are different opinions about the pH-KH table to measure the CO2 levels on this forum; mainly that you cannot trust it. (I to new to know what's true)

Reading the table I have > 120 ppm CO2 at pH 6.3? - wow! So your advise is that I should adjust the CO2 to get a drop from pH 8.2 to pH 6.9 as a maximum? 

Will the change of the available amount of CO2 have any negative effect on the plants? It will have effect in the duration of my CO2 bottle


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## ian_m (15 Sep 2014)

Don't rely on the table as that assumes carbonate hardness/buffer is the only "salt" in the water, which as this is a fish tank, it won't be. You will get ridiculous funny values.

What does your drop checker say...green....green/yellow ? This is liable to be correct as it is isolated from the complete unknown called "your tank water this afternoon" as well as "your tank water this morning" and even "your tank water last night". 

Are you sure you have your Easy-Carbo dosing right ? I thought 1ml per 50litres.

Shrimp can be "not happy" in too much easy carbo.


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## mede (15 Sep 2014)

thanks for your reply Edwin and Ian!

Well this is exactly what I mean; two different opinions - which one to follow? I also read several post on this forum that the drop checker isn't the right tool to measure CO2.

Some discussion on this forum are talking about a pH drop of approx. 1 if you have a KH value of 8 - 10. Clive explains this a few times and I see lots of people following his advise.... who can convince me what to do with my CO2 injection based on my pH profile?

I'm not ignoring any advise, but I'm confused about all different opinions/advises here and I want to do it all right of course 

I'm injecting lots of CO2 during the startup of the tank as there is nothing but plants in it right now.


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## ian_m (15 Sep 2014)

mede said:


> I also read several post on this forum that the drop checker isn't the right tool to measure CO2.


The definitive article on CO2 levels in your planted aquarium is here: http://www.ukaps.org/index.php?page=co2-measurement-using-a-drop-checker. Follow that, can't go wrong.

Yes you can use a pH drop of 1 a handy start, but what is your KH, how accurate is it, how accurate is your pH meter, especially when contaminated with tank water. Most test kits don't measure KH, but alkalinity. Dead plants, dead fish and any ammonia present, especially in new tank, will adversely affect a hobby test kit KH reading, probably rendering the reading useless.


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## EnderUK (15 Sep 2014)

Both are tools to be used with the drop checker an inaccurate range on a calibrated scale with the pH accurate on a scale you don't know the range of. So use both. Chances are your live stock will be from aLFS that has low CO2 high O2 water so best starting the co2 low and build it up over a couple of days while keeping watch. If you see gish struggling turn the CO2 back down and do a big water change.

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## ian_m (15 Sep 2014)

EnderUK said:


> and do a big water change


Or air stone on.


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## EdwinK (15 Sep 2014)

ian_m said:


> Don't rely on the table as that assumes carbonate hardness/buffer is the only "salt" in the water, which as this is a fish tank, it won't be. You will get ridiculous funny values.
> 
> What does your drop checker say...green....green/yellow ? This is liable to be correct as it is isolated from the complete unknown called "your tank water this afternoon" as well as "your tank water this morning" and even "your tank water last night".
> 
> ...



You are not quite right. Table is reliable because values are calculated by the simple formula. Actually, consumer grade kH tests are not reliable and if you get wrong results from incorrect initial data that's not the table to blame.


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## mede (15 Sep 2014)

My water company reports a KH of 8 and I also measure this value with a KH drop test kit. 

Isn't a drop test based on the number of drops quite accurate as you don't have to guess based on a vague color? I'm pretty sure that the pH is quite accurate measured with my calibrated pH pen.


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## EnderUK (15 Sep 2014)

It's based off measuring alkalinity so not really accurate. I have no idea how much CO2 ppm I have in my tank I just know it's the maximum I can put into it without stressing out my fish. If my rainbows start hovering around my tank surface then I back off the CO2 a hair turn.


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## ian_m (15 Sep 2014)

mede said:


> My water company reports a KH of 8 and I also measure this value with a KH drop test kit


Great you have just measured you tap water, which does not contain the ammonia, rotting plant debris etc that makes test kits completely unreliable. Same with pH, fine if just acid/alkali in water, but your tank has loads of other "stuff" that will affect the reading, which is why the test kits can't be relied on



EdwinK said:


> You are not quite right.


Sorry, you are correct this is water untainted by being in a tank. As has been said many times this should be used as a guide to give an idea how much CO2 to add. The drop checker generally is the definitive answer


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## mede (16 Sep 2014)

ian_m said:


> Great you have just measured you tap water, which does not contain the ammonia, rotting plant debris etc that makes test kits completely unreliable. Same with pH, fine if just acid/alkali in water, but your tank has loads of other "stuff" that will affect the reading, which is why the test kits can't be relied on



Thanks Ian!

Are you really telling that pH meters are not reliable? What about the automatic CO2 systems that keeps the water 24/7 on a certain pH level based on the adjustment in the pH computer? At the moment I'm doing 60% water change with tap water every second day; will there really be "loads of stuff" that affect the reading? 

Lowered the CO2 injection a little bit yesterday. Now I measure a pH of 6.7 between 18:00 and 20:00 (= lights out). Still a pH drop of 1.6 but the drop checker is more green now compared to previous days (more yellow). Maybe adjust it a little more so I reach 6.8 at this timestamp and put in some shrimps this weekend.


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## EdwinK (16 Sep 2014)

I would like to know what is that "other stuff" that could affect H+ and OH- concentration as well.

mede just be aware that Amano shrimps are extremely sensitive to high CO2 concentrations.


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## mede (16 Sep 2014)

Looking at your tank Edwin; really a beauty! How do you decide the amount of CO2 you put in your tank?


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## ian_m (16 Sep 2014)

mede said:


> Are you really telling that pH meters are not reliable?


Yes in tank water as there are many things that can affect a pH meter other than pH. Generally I think you will find people who use a CO2 computer (actually pH)  to control their CO2 levels fail and have fluctuating CO2 leading to massive algae issues. "hobby" pH meters/test strips etc are really only accurate if there is only acid (or alkali) in the water, in our tanks there is carbonate, sulphate, nitrate, phosphate, chloride etc all unknown and all these things can lead to a false reading.

I think ages ago someone found that one of the hobby test kits pH reading were severely affected by chloride in the water.



EdwinK said:


> I would like to know what is that "other stuff" that could affect H+ and OH- concentration as well.


Not the H+ and OH- being changed but things like chloride causing under/over reading of pH on test strips.


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## pepedopolous (16 Sep 2014)

Sure there's lots of other things that can lower pH but if you start injecting CO2 at say 8:00 and by 10:00 the pH has decreased, you can be pretty sure that the change was caused by the CO2 only. This will be confirmed by the pH increasing after CO2 is switched off.

P


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## EdwinK (16 Sep 2014)

ian_m said:


> Not the H+ and OH- being changed but things like chloride causing under/over reading of pH on test strips.



We are talking about pH meters here, not the test strips. Most probably fluctuating ph levels on ph meter are caused by cheap probe, dirty probe or not calibrated device.



mede said:


> Looking at your tank Edwin; really a beauty! How do you decide the amount of CO2 you put in your tank?



Thanks for your kind words. I use kH pH table as a rough reference.. Then I gradually increase amount of CO2 and watch for reaction of my fish. At the point where my fish start to strugle I turn CO2 a bit down. Also in both of my tanks I have a high surface movement to ensure a proper gas exchange.


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## EnderUK (17 Sep 2014)

EdwinK said:


> I use kH pH table as a rough reference.. Then I gradually increase amount of CO2 and watch for reaction of my fish. At the point where my fish start to strugle I turn CO2 a bit down..



Well if the kH and pH tables were accurate you would not need to do this since you would have exactly 30ppm and that's all the plants need. You just said you used it as a rough guide so it really can't be that accurate just like the drop checker is a rough guide and so is using your fish stress levels. You kind of have to use all 3 to maximize CO2, help monitor the CO2 levels and even then you don't know what those CO2 levels actually are.


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## EdwinK (17 Sep 2014)

Maybe you guys don't get me because English is not my mother-tongue language so I'll repeat my self once more. pH kH table is very accurate since it is calculated from this C(co2)ppm = kh*3*10^(7-pH) simple formula. I use the table as a reference just because I do not have a kH and pH tests that I can trust however mede here and his tap water provider know that his kH is 8 degrees and he has a digital pH meter that shows him the exact level of pH and he do not need to guess what colour he sees.
Actually I do not care how much of CO2 is in my tank is it 20 or 40 ppm because I'm trying to ensure maximum safe levels for my fauna. I hope you do understand that every tank is unique due to its water chemistry, flora and fauna. So if 40 ppm of CO2 for my Hemigrammus rhodostomus is ok it could be very possible that 30 ppm of CO2 for your Amano shrimps is lethal. And also one should not forget about the O2 levels in the tank. So if I have maximum O2 in may tank maybe 40 ppm is comfortable for my fish but on the other hand if there is minimum O2 the 20 ppm could be a challenge for fish.
Hope this time you will understand my point.


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## EnderUK (17 Sep 2014)

I understand, I'm pointing out that following one method is not the best way. They are tools to help monitor levels of CO2 but neither method is accurate. So we're arguing the same thing and as you said every tank is different.

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## ceg4048 (17 Sep 2014)

mede said:


> I am afraid that the pH drop from 8.2 to 6.3 is too much for the Amano shrimps and fish (Rasbora). Every day a pH swing of almost two points. I don't want to use the animals as test material to see if it's OK to add them to the tank. What is your opinion?



Hello,
        As mentioned earlier it's best to stick with the basic numbers and use the tools at hand to guide you. Assuming you increased the CO2 injection rate to help the plants, you can now reduce the injection in order to accommodate the fish. This is normal. Instead of a 2 unit pH drop, aim for a 1 unit drop and also reduce the lighting by say, 50%. This slows the growth rate and allows the plants to adjust to the lower CO2 availability. This takes about 2-3 weeks and then you can slowly increase the lighting if desired.

Additionally, use the basic rule of thumb regarding the DC. If the DC is lime green or darker by lights on and if it does not drop into the yellow, then this is a sign that the CO2 levels are not too extreme.

Shrimp are more susceptible to hypercapnia so it would be better to add fish first.

Cheers,


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## mede (17 Sep 2014)

thank you for all advises guys, much appreciated!

At the moment my my pH is 8.2 in the morning (lights off) and is 6.7 around 18:30 (15:00 lights on). I will lover the CO2 injection a little bit more and add fish in stead of shrimps the coming weekend. I also put the lights a few inches higher above the tank. I'm injecting CO2 through the inlet of my filter (Tetratec Ex600).

It's hard to see, but my drop checker isn't yellow but more light green. I have doubts if I can trust my drop checker solution. I'm using a selfmade 4 dKh solution and add some drops of JBL pH 6 - 7,6 to it (10 drops). Does anyone know if I can get a ready to use solution which is accurate and is available on Ebay or a webshop that ships to the Netherlands?


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## Andy Thurston (17 Sep 2014)

mede said:


> thank you for all advises guys, much appreciated!
> 
> At the moment my my pH is 8.2 in the morning (lights off) and is 6.7 around 18:30 (15:00 lights on). I will lover the CO2 injection a little bit more and add fish in stead of shrimps the coming weekend. I also put the lights a few inches higher above the tank. I'm injecting CO2 through the inlet of my filter (Tetratec Ex600).
> 
> It's hard to see, but my drop checker isn't yellow but more light green. I have doubts if I can trust my drop checker solution. I'm using a selfmade 4 dKh solution and add some drops of JBL pH 6 - 7,6 to it (10 drops). Does anyone know if I can get a ready to use solution which is accurate and is available on Ebay or a webshop that ships to the Netherlands?


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