drop checker


Feb 16, 2007
Hi Tom
I been trying to raise the CO2 level in my tank to destroy some persistent BBA and have a question re CO2 readings.
I have a 40g tank with DIY inline external reactor running off a Eheim 2217 which seems to create pretty good water movement around the tank. I have been using an ADA drop checker(4 DKH). A second eheim is used to make good surface movement. Lights are on 10 hrs with CO2 on 2 hours before light on and off an hour before lights out with 2.5 w/g of light.
In the morning the drop checker is a blueish green colour and at 3-4 bubbles/sec it is a nice light green a couple of hours after light are turned on.
It seems that even if I start CO2 again in the morning 2 hours prior to light coming on the checker takes a while to change colour.
Should the drop checker be the colour I want (namely a nice light green colour) when the lights come on?
There appears to be some pearling after about an hour which seems good I think...
I have been trying to beat this BBA by getting my conditions consistent and have not yet tried any Excel.I'm pretty sure my ferts are good and that this is a CO2 issue. BBA is only on crypts and Anubias. Faster growing plants are all growing well and BBA free.
Many Thanks