I recently set up a client's 125G w/sump using a Sedra 9000 Needle Wheel pump (900 GPH @ 13' Head) for return (3/4" split into two return lines). The pump does a great job with water flow, even with the needle wheel's lower than spec GPH performance, and it fills the tank with an incredible CO2 mist, but the client reports that he is unable to drop the pH below 6.8 (KH 2-3). I need to hit a pH of 6.3 or 6.4 to feel comfortable with CO2 levels in this tank.
I'm going to be checking the install out this week and thought I would run this issue by you guys before I went. Here are my thoughts as to why pH is not dropping: 1] Improperly calibrated pH controller; 2] Improperly adjusted CO2 flow rate from regulator; 3] Excessive flow from Sedra 9000 (may need to throttle with ball valve); 4] Possible air bleed into CO2 line running to Sedra pump.
I calibrated the controller, set the CO2 bubble rate, and connected the CO2 line to the pump myself and am reasonably sure they have no issues but I will double-check when I go to the client site. I am currently leaning toward excessive flow as a possible cause of the problems because I can't come up with any better reasons. If you've got any advice I would greatly appreciate it. Thanks!
I'm going to be checking the install out this week and thought I would run this issue by you guys before I went. Here are my thoughts as to why pH is not dropping: 1] Improperly calibrated pH controller; 2] Improperly adjusted CO2 flow rate from regulator; 3] Excessive flow from Sedra 9000 (may need to throttle with ball valve); 4] Possible air bleed into CO2 line running to Sedra pump.
I calibrated the controller, set the CO2 bubble rate, and connected the CO2 line to the pump myself and am reasonably sure they have no issues but I will double-check when I go to the client site. I am currently leaning toward excessive flow as a possible cause of the problems because I can't come up with any better reasons. If you've got any advice I would greatly appreciate it. Thanks!