[Jane in Upton]

I have a question for those of you adding some CO2. I don't mean to hijack your thread racialfish, but it's part of the answer for your question, too.

CO2 addition will obviously increase the growth rate of the plants (and therefore the accumulation of allelochemicals in the soil will be faster, and more likely to outstrip the rate that bacteria would break them down). Do you folks who supplement CO2 also dose fertilizers to the water column? And if so, is the water column dosing more or less in proportion to your CO2 addition? Bpimm says they don't add large amounts of CO2, but what about fertilization rates? It seems to me, being a casual observer of the high-tech method, that the trend is for ever increasing levels of CO2 and Ferts (they usually seem to go hand in hand).

Also, those of you adding CO2 to a soil substrate tank, are you using a DIY, or pressurized system? My thought is this - with DIY, it seems that the CO2 levels are more variable as the yeast concoction ages, and I'm wondering if the levels of CO2 addition are on the low side anyhow, I'd imagine that the tank might be more resiliant to these fluctuations. Or, is it the opposite - at lower levels of CO2 addition, consistency is paramount in order to see the results?

I recall its been brought up that the soil substrate could possibly become exhausted faster if everything was ramped up (ie, CO2 addition, fert addition, etc.). Have any of you adding CO2 experienced this?

Thanks in advance for your input.
-Jane