I tested this morning KH of 12 and PH of 7.8 (was KH 11 ph 8.2 CO2 2.1
eleven hours into the light) which works out to CO2 of 5.7 ppm. So the CO2
injection is working.

Not very well. In the morning, your CO2 levels should be at their highest.
5.7 ppm is barely above the levels normally found in water. That's why your
CO2 levels are so low later in the day, after your plants have been
photosynthesizing while. They actually drive CO2 levels down below normal, by
using it all up.

You have to increase your CO2 levels. Either reduce surface agitation, or
increase the size of your yeast-sugar batch. You want your pH down around 7.2.


Leigh

http://www.fortunecity.com/lavender/halloween/881/