What Time To Test Co2

[WendyinWichita]

I have read the pinned article regarding CO2 (many times) and I am a bit confused regarding when is the best time to do my water tests to determine CO2 amounts. The article indicates to test before lights on, and after lights off. My questionis, how long after lights off should I wait to test? I would think if the lights click off and I test, the results won't be any different than when lights are on.

Secondly, it seems the goal for CO2 is 30ppm (amongst this forum), however, the article indicates 30 is dangerous to fish. Has the standard changed since the article was written? I have struggled to get my levels up to 30 (2 diy bottles and 1 Hagen unit finally achieved that level). The tank in question is a 55 US gallon.

 

[houndour]

This is my interpretation...

I would say test either just before or just after. I test within an hour of the lights turning off.

I guess the main thing is to be consistent. pH levels will fluctuate over the 24 hour cycle and so will the CO2. So testing one day at 9am and then comparing it to results the following day at 9pm might give you quiet different results. (my pH is 6.4 in the evening and 7 in the morning - but I turn my CO2 off overnight).

The amount of CO2 is unclear on a lot of websites. I've read sites that say over 25ppm is dangerous. I personally keep my CO2 between 30 and 40ppm. CO2 does not displace O2, or so I have been told. Obviously keep an eye on your fish and if they ever look like they are gasping for air then stop the CO2 and add an airpump/or position you filter to create bubbles. Other than that nobody seems to know what the affects of too much CO2 is. Keep an eye on the pH as a sudden drop/increase can be fatal to fish.

 

[Rooster]

CO2 does not displace O2, or so I have been told.

Then you have been told wrong ! That is EXACTLY how a CO2 fire extinguisher works !

 

[pseud]

Then you have been told wrong ! That is EXACTLY how a CO2 fire extinguisher works !

When was the last time you had a fire in your tank?

 

[pseud]

Also, it's best to test your CO2 levels before lights on.. preferably after they have been off all night, so right before lights come on in the morning is good. Aim for 30ppm.

 

[houndour]

Also, it's best to test your CO2 levels before lights on.. preferably after they have been off all night, so right before lights come on in the morning is good. Aim for 30ppm.

Unless you use a solenoid (for pressurised) like me. If I tested before lights on I'd take a guess that it wouldnt be at optimum ppm. Although I do turn the co2 on about 45 mins prior to lights on.

 

[pseud]

Unless you use a solenoid (for pressurised) like me. If I tested before lights on I'd take a guess that it wouldnt be at optimum ppm. Although I do turn the co2 on about 45 mins prior to lights on.

Good point!