Planted Tank Guru
Join Date: Feb 2010
Location: Newbury Park, CA
Yeah, the durso is just expelling the air bubbles+whatever CO2 diffused out as the air/water fell through the pipes. A herbie oughtn't do that. I don't really care that much that the sump is wasting gas, gas isn't all that expensive compared to all the rest of the monthly expenses. Just increase the gas to the level that works for your plants and animals.
Your pump is lifting 500gph? I would want to split the flow too. My RIO 2500 only lifts 300gph because of the height, length and all the right angles in my set up and does fine with the little 3"x12" reactor.
Try cutting back on the lighting period. I was helped out in this by my plants. Wisteria, Myriophyllum and Rotala all were closing up their leaves before the lights went out so I reduced the hours until they closed up just before lights were out, about 8 hours of full light. Maybe try 10 hours total with 4-6 hours with all the bulbs lit.