Low pH In reef tank 7.39-7.8

[E13MentX]

I have been struggling to keep my pH up in my tank especially at night. It gets as low as 7.39 at night and 7.8 during the day. I triple checked that the pH reading is correct with 2 different probes and 2 different handheld pH meter. I have tried many different ways to increase the ph with no success. I am currently running full zeovit system with a calcium reactor. But to help with low pH I turn my calcium reactor off at night and dose kalkwasser at night using a doser. (20 ml every hour for 12 hours starting at 11 pm). I don’t see any change other than my alkalinity going up. I am also running a recirculating co2 scrubber. But the co2 scrubber never had any improvement in my tank. I tried to reverse cycle my sump (AI PRIME with a few frags). Is there anything else I can do to increase the pH? I like to keep my alkalinity around 7.8. Usually I don’t try to chase numbers but for some reason my pH is absurdly low. I do not know how long the pH problem has been going on because I only started monitoring my tank pH when I picked an apex a few weeks ago. I am worried that low pH is the reason I lost a few frags and why I have little to no growth for the past year. Thank you for your help in advance!

 

[Sick_man]

run a refugium so the ph doesnt drop at night

 

[E13MentX]

run a refugium so the ph doesnt drop at night

I had a refugium but my nutrients was too low so I had to take it out several months ago

 

[92Miata]

Something is wrong here.


The atmospheric CO2 required to drive 8dkh water to 7.4 pH is absurd. At 1000 ppm atmospheric, you're in the 7.8 range. And pH is logarithmic, so 7.4 is waaaay lower than 7.8.

Your calcium reactor has to be dumping comically high levels of co2 into the tank

 

[Nick Steele]

Something is wrong here.


The atmospheric CO2 required to drive 8dkh water to 7.4 pH is absurd. At 1000 ppm atmospheric, you're in the 7.8 range. And pH is logarithmic, so 7.4 is waaaay lower than 7.8.

Your calcium reactor has to be dumping comically high levels of co2 into the tank

mid there a formula for this? I’m in the same issue although a much smaller swing of 7.6-7.9

 

[92Miata]

mid there a formula for this? I’m in the same issue although a much smaller swing of 7.6-7.9

Randy has some old reefkeeping magazine stuff.

http://www.reefkeeping.com/issues/2004-09/rhf/

 

[E13MentX]

Something is wrong here.


The atmospheric CO2 required to drive 8dkh water to 7.4 pH is absurd. At 1000 ppm atmospheric, you're in the 7.8 range. And pH is logarithmic, so 7.4 is waaaay lower than 7.8.

Your calcium reactor has to be dumping comically high levels of co2 into the tank

I do agree that something is wrong but I can’t figure out what is. I don’t think it is my calcium reactor anymore because I turn it off at night for 12 hours and my pH still drops crazy low. (The was what I suspected at first so that’s why I turn it off at night) but you can see that in my apex the calcium reactor ph is around where my tank is since it was off. So I’m trying to figure out what is wrong

 

[vanpire]

I would check your calcium reactor set-up to see it is not leaking any CO2. Check your gauge connections and valves. Better yet, turn off the valve on your CO2 tank and open the doors to the sump (assuming the CARx is in the sump or near the tank). Continue with Kalk dosing to stabilize your ALK and see what happens.

 

[uninformed]

@E13MentX, were you ever able to figure out the cause of the low pH? How did you correct it?

 

[E13MentX]

@E13MentX, were you ever able to figure out the cause of the low pH? How did you correct it?

I was not able to find the cause but I added a co2 scrubber as well as using kalkwasser to help boost my pH a bit