I have a 38 gallon tank w/ 96watt light. 2 Bio Wheel filters (each made for 50gal capacity). It has been set up as a low light tank for over a year, and I just made the switch a few weeks ago. I am beginning to get both types of algae growing, and desided the largest factor must be the lack of co2. But from what I read, co2 LOWERS the PH. This is a problem as for what ever reason, my PH already goes lower on its own. I constantly have to add baking soda to my tank to bring it back up, and dont know why it won't regulate. Ammonia Nitrate and Nitrite levels are fine. What could my problem be?