I bought a 77301-20 benchtop system and some far things are not as stable as they should be, at least from what I've seen on here from other members.
I'm have the pump set at 50ml and the AP regulator at 1 bubble every 10 seconds. Output Co2 pressure it's about 6psi. I'm not worried about getting the pH to the correct level just yet. I first wanted to see how stable this thing was but so far I'm not impressed.
Tank pH swings from 8.2 to 7.8-7.9 thought the day.
Calcium reactor swings from 7.53 to 7.36
Anybody experience similar pH swings? Could I be doing something wrong or is this pH swing in the reactor simply due to the tank pH swing?
how is the c02 solenoid being controlled, ie is on all the time or is it cycling on and off
On all the time.... its not in the range that my apex would shut it off.
For starters, your reactor pH will swing a bit and follow the swings of your display from day to night. That is normal. pH drops at night and increases during light on hours due to increased o2 from photosynthesis. I have to question the swings you are noting in the display though. That leads me to wonder if your display's pH probe is seeing interference or perhaps calibration is off. A .2 change is pH from day to night would be expectable but going from 8.2 to 7.8 is a bit excessive unless you have a major algae issue in your tank. In that case, I would expect similar fluctuations in your reactor.
My tank has always swung that much. Especially if windows are open during the day and shut at night.
If Windows are shut 24/7 then it's a smaller swing.
No algae problems either.
For starters, your reactor pH will swing a bit and follow the swings of your display from day to night. That is normal. pH drops at night and increases during light on hours due to increased o2 from photosynthesis. I have to question the swings you are noting in the display though. That leads me to wonder if your display's pH probe is seeing interference or perhaps calibration is off. A .2 change is pH from day to night would be expectable but going from 8.2 to 7.8 is a bit excessive unless you have a major algae issue in your tank. In that case, I would expect similar fluctuations in your reactor. That said, what ever the cause is, it likely has nothing to do with you calcium reactor unless the reactor effluent is entering the sump right next to or up stream of the pH probe.
As a side note, 50 ml/min may end up being way too much flow but it all depends on the amount of SPS or calcium uptake and the size of the system. I run at 24 ml/min with 1 Co2 bubble every 6 seconds.
I guess what I wanted to know is if a .2 change in the reactor will cause a significant drop/increase in the effluent ALK concentration?
That won't really impact anything. I think pretty much all of us face the similar fluctuations in pH within our reactors. It's all about finding a balance of what flow works best to maintain the Ca and Alk levels that you are targeting in your tank . Different media has different recommended pH ranges and in my case, I loosely based my target reactor pH on those numbers as a starting point for my Reborn media. Some test the Alk from the effluent while others don't. I test my tank water and base my reactor adjustments on the tank water and never bother to test the levels of the effluent.
My PSI is 12 and I'm at 60bpm, which results in a stable 6.6ph at 30ml per minute. Also, it looks like it should be very stable and consistent over time.
ZenMan,
Looks like a Mini Cal, if so it's way under rated for that system, you need the Pro Cal.
That is what I don't understand. My PSI is 3 and 7.6 BPM and my PH is 6.6 at 40ml/min. If I ran at your numbers I can't imagine how low my ph would go, or maybe there is a floor?