I have a 70 gallon RR Oceanic with 22 gallons in a sump and I installed 90 pounds of Marshall live rock five weeks ago and another 30 pounds of Live Aquaria "Lalo rock" about three weeks ago. My chemistry is good as far as I can tell, The smell went away in five days, the ammonia level was not measurable after ten days and the nitrates have gone below .3 mg/l, calcium is always over 450 ppm and frequently above 500. I run 580 watts of light four hours a day and use AquaC two part to maintain PH and calcium. I have some green, mossy looking algae growing on some of the rock surfaces and some purple starting to come out. My question is: I turned off the water flow to see if I could see bugs or worms and saw instead, alot of very fine bubbles arising from the rock. I assume this is decay in the rock producing CO2 and that this is what is causing my Ph to drop from 8.3 to 8 or slightly less every two days and requires me to dose to raise the ph to 8.3. Please comment on whether my assumptions are correct and how much longer can I expect to have this CO2? Also, I intend to do a 30% water change and put in a cleanup crew this week. Does that sound O'K?



