(OLH) Optimum Light Height

[alkbud]

Was wondering what is the optimum light height for a 250W HPS. and secondly how much bicarbonate of soda and vinegar produces 1/2 cubic ft of CO2?

[caroline]

as far as i know you don't get co2 from bicarb and vinegar, use yeast and sugar which will forment making co2 and you can use bicarb as a stabalizer (well you do with injecting co2 in a fish tank anyway).