Tom,

You are a great resource. Thanks for your replies.

A question that struck me this morning. You mention you mix Flourite or Onyx
gravel with Peat. Wouldn't the humic acid from the peat mess up your CO2? How
do you measure CO2 in a planted tank with peat? Do you need to use a test kit
to measure CO2 (i.e., to measure CO2 more directly rather than inferring CO2
levels from carbonate hardness and PH) or does the humic acid not really
matter?

Also, is the study you referred to on substrate heating available on the
Tropica web site?

Thanks.

Bruce