I think Tom Barr made some comments recently about this? If the CO2 is in doubt, simply add 5-10ppm more CO2 and monitor the fishes behaviour. If the fishes are fine, add the full 10+ ppm of CO2 should get you to the close range of the 20-30ppm. Anyway, critters are the limit of how much CO2 you can pump in. The plants simply love it when it is high and good. [:]
Regards
Peter Gwee
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