When I set up my 15 gallon Aquaosoil tank, I purposely used 2 DIY C02 bottles, and an additional Hagen c02 system. Diffusion of the c02 was with a modified Hagen submersible filter and Rhinox ceramic diffuser. The idea was to bombard the tank with c02 to jump start the plants which were in pretty pathetic condition. It seemed to work all too well with the drop checker reading a constant yellow, indicating 40 PPM c02. Surpisingly the snails appear to be unphased by the c02 assault and appear to be thriving, even though there are no other inhabitants in the tank and no feed is being used.

So, my question is, how do I throttle back on the c02 gradually to prevent a huge algae bloom from any temporary c02 inconsistency that thottling back may cause. I really don't want to put fish and shrimp in there if the c02 levels are 40ppm as I would hate to have them succumb to c02 poisoning. However, I have to question the accuracy of the c02 drop checker since the snails appear unphased and appear to be replicating. So, should I reduce lighting from 40 watt compact fluorescent to 30 watt compact fluorecent and remove the hagen co2 system and one bottle. Will one 2 litre c02 bottle be enough or willl throttling back like this on the c02 ignite an algae bloom.

Any suggestions, recommendations, and ideas would be most welcomed. Many thanks.

You can try adding more surface disturbance. Aim a powerhead or other flow source more towards the surface so you get light rippling. That will cause more of the CO2 to be lost, and reduce the ppm somewhat. I doubt that a drop from around 40 ppm to around 30 ppm will cause an algae bloom.

Just to be sure about your conditions: are you using 4 dKH distilled or deionized water in the drop checker and not tank or tap water?

Thanks Hoppy

I don't know about adding another power head. I already have two Hagen Elite Subemersible filters modified to act as diffusers and combined they are providing quite a bit of circulation. Additional surface agitation is being provided by the Aquaclear 150 HOB filter.

Perhaps I will set an airstone attached to an airpump on a timer and run it at nightime only when c02 is not as critical for the plants.

Try changing the DIY brew.

you can change the volume of CO2 produced that way.

You can alternate week to week which bottles are changed.
You can change the amount of Yeast added or Sugar
Gelatin, etc. Heat, cool the bottles etc.


Regards,
Tom Barr

Thanks Tom