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Advice running 24/7 CO2

kschyff

Member
Joined
29 Jun 2020
Messages
132
Location
Dundee, Scotland
I had some instability with CO2 and got black beard issues creeping up on me. I have changed to a 24/7 regime at just under 1bps in a very small 60cm shallow tank. The DC is far on the right where no bubbles are and is permanently yellow/green (mostly yellow). Flow is adjustable and currently not super strong but does create a nice flow around the tank. How could I further tune this so I can get as much stability as possible? My Ph pen is really not that great and reads 7.2 which is nonsense if the DC is yellow/green. Any advice will be appreciated as I can see the plants are not happy. ADA soil that about 2 months old using ADA ferts as prescribed.
 

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I had some instability with CO2 and got black beard issues creeping up on me. I have changed to a 24/7 regime at just under 1bps in a very small 60cm shallow tank. The DC is far on the right where no bubbles are and is permanently yellow/green (mostly yellow). Flow is adjustable and currently not super strong but does create a nice flow around the tank. How could I further tune this so I can get as much stability as possible? My Ph pen is really not that great and reads 7.2 which is nonsense if the DC is yellow/green. Any advice will be appreciated as I can see the plants are not happy. ADA soil that about 2 months old using ADA ferts as prescribed.
@kschyff I have no experience with CO2 injection, however the plants wont be using it outside the photoperiod (where they use oxygen instead of CO2).... so, I suppose it will just dissipate and go to waste, on the other hand there will be plenty when the lights come on (usually, the CO2 injectors turn it on about an hour before lights come on). Also, algae issues in injected tanks are usually associated with a poor CO2 setup / flow/circulation / too much light vs. CO2 levels etc. But I yield the floor to someone with more knowledge :)

Cheers,
Michael
 
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Plant health looks okay. When you say you had BBA issues, where was the BBA growing? On the plants or on hardscape/equipment?
 
Water changes are now every three days but was weekly. The BBA is on the older plant leaves and hardscape. When I do a water change I scrub it off with an electric toothbrush and I cut off the infected leaves, hence there is not much visible in the picture.
 
The DC colour looks good IMO/IME. Just as a check take a glass of tank water a few days after a WC and leave it 24hrs then take pH of water in glass and compare it with the pH of the tank which was taken when you filled the glass of water.
What clean up crew do you have ? (snails/shrimp)
 
Thank you Zeus. I currently have 2 ottos and 3 Amano's.
Some RCS (Red Cheery Shrimp) would help also, I was always cheeky at LFS and ask How many do I need to buy to get your best price - got them down to £2.00 each and they was pretty decent RCS as well good reds. the big plus of RCS is they will breed in tank as well, only downside of RCS is some fish eat them - my SAE ( Siamese Algae Eater) got a taste for them which held them back, relocated the SAE and population soon when over 1000 in 500litre
 
Hi Zeus. I don't quite know how to interpret this, but the water in the cup has a higher pH of 8.0 than the water in the tank which is 7.4. The pen must ridiculously faulty as the DC is yellow/green. What do you think? I have made no adjustments now for just about a week. Last water change was 4 days ago.
 
Hi Zeus. I don't quite know how to interpret this, but the water in the cup has a higher pH of 8.0 than the water in the tank which is 7.4. The pen must ridiculously faulty as the DC is yellow/green. What do you think? I have made no adjustments now for just about a week. Last water change was 4 days ago.
If you are injecting co2 you expect the ph to drop due to the dissolved co2 in the water. The aim is to have the tank at 1ph lower than the water you kept in the glass degassed. So I would suggest you have the correct readings. Maybe the water in the cup hadn't fully degassed. Dc is subjective to what we all say is the correct green. My dc looks slightly yellow to me but fish are fine and ph drop of 1 is steady
 
If DC is yellow/green, it would suggest that pH is less than 7.0? So if the pH pen says 7.4, there seems to be an issue.

Regarding degassed pH vs initial reading, 0.6 difference sounds normal.

Another question for the experts: can the pH reading of water in a cup vs in the tank also be skewed by the pH buffering effect of aquasoil in the tank? i.e. when you move the water to a cup to let it stand, there is no more aquasoil to buffer the pH?
 
In my experience, mini-landscape stones (aka Seriyu stones) release calcium in CO2-injected tanks and buffer the tank's water pH.
@kschyff, I believe your pH pen is ok; the drop checker is yellow because it indicates the "actual" level of dissolved CO2. pH reading, on the other hand, is an indirect measure and it's affected by other factors. In your case, I guess, mini-landscape stones raise the kH of your tank water, so you get pH of 7.4 with high levels of dissolved CO2.
 
Thank you Sergey. I am new to all this so does this mean that the plants are in a more optimal environment? I ask this as the information I have read and watched on YouTube states that the plants require slightly acidic conditions. I suppose my actual question is can I ever measure the "actual" dissolved CO2?
 
If DC is yellow/green, it would suggest that pH is less than 7.0? So if the pH pen says 7.4, there seems to be an issue.
The pH in the drop checker is independent of the tank water. Did you use commercial drop checker fluid? Or make your own with 4DH water?
 
You should be fine with the fluid, it should be 4DH.
It measures the pH in that fluid, which changes with the CO2 level. CO2 diffuses from the tank water into the air space in the drop checker and then into the fluid. There's a bit of a time lag while that happens, but after that the pH change in the DC will reflect the CO2 level in the tank water. The pH of the tank water can be different, as there are other factors affecting it. Those don't affect the DC. So your pH pen could well be accurate. If you want to check it, you can get calibration solutions of known pH to test it with. And some pens are adjustable, check the instructions for your one.
hth
 
Relatedly, I just started the lights on another 60p that has been in a dark start for 2 months while I waited for plants. I am trying the same approach in this new tank and also added an airstone when CO2 is not running. So far I am reading the pH at 6:30am, 17:00 and 21:30 and the pH ranges from 6.4 to 6.7. Is this the "sweet spot"?
 
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