High PH that won’t budge

[Brokecoloadoreefer]

Worried about high PH and I can’t nail down the cause. Or should I even be worried.

My PH has been on a upward trend for the last 4 days or so. Currently is 8.35 at night and will peak out to 8.67 before lights out.

The tank is 200 gallons. About 3 months old. Total system volume is around 350 gallons. Things that I am using that could affect PH:
CO2 scrubber.
Calcium Reactor
Auto water exchange (5 gallons per day )
Lighting is 5 radion XR30 blue running at 50%

What I have done to try to isolate:
Unhooked scrubber. No change.
Turned off Kalk. No change.
Increased reactor output by 50%. No change.

Any ideas ? There is over 100 SPS corals in this tank and every single one is thriving in terms of growth and color. They look amazing. But I know how fast that can change.

 

[Randy Holmes-Farley Verified Community Expert]

If accurate, low CO2 is the only reason for pH to be high (assuming alkalinity is not excessively high).

Why are you using a scrubber? Stop using it, if the pH is real.

More aeration will reduce it, if real.

 

[Joedubyk]

re-calibrate your pH probe. I highly doubt you have a ca reactor and it's that high. id bet money

 

[Brokecoloadoreefer]

If accurate, low CO2 is the only reason for pH to be high (assuming alkalinity is not excessively high).

Why are you using a scrubber? Stop using it, if the pH is real.

More aeration will reduce it, if real.

Thank you Randy. I implemented the scrubber when I wanted to boost a bit out of the high 7’s. And I like gadgets lol. The pH is real. Verified to be .01 with a lab grade pH meter and close with read sea drip kit

Right now the scrubber and the kalk are offline. Just running the reactor.

 

[Brokecoloadoreefer]

re-calibrate your pH probe. I highly doubt you have a ca reactor and it's that high. id bet money

It’s calibrated and cross verified. Thank you for replying !

 

[Garf]

It’s calibrated and cross verified. Thank you for replying !

You must have a lot of photosynthesis going on. You got a refugium also?

 

[Brokecoloadoreefer]

You must have a lot of photosynthesis going on. You got a refugium also?

Yea , about 15% tank volume fuge with two kessil 160 grow lights over it. Macros are dense and dark green.

 

[Garf]

Yea , about 15% tank volume fuge with two kessil 160 grow lights over it. Macros are dense and dark green.

That could do it then.

 

[Brokecoloadoreefer]

That could do it then.

Interesting. It’s also managed to wipe out any trace of nitrates and about .01 of phosphates and I’m dealing with a pretty good diatom bloom. But that’s another story

 

[Randy Holmes-Farley Verified Community Expert]

Do you have a skimmer providing aeration?

 

[Joedubyk]

It's simple, Just program your apex to turn your skimmer off when you 're over 8.5, turn back on when 8.1

 

[Brokecoloadoreefer]

Do you have a skimmer providing aeration?

Yes sir. A regal 250 ext.

 

[Brokecoloadoreefer]

It's simple, Just program your apex to turn your skimmer off when you 're over 8.5, turn back on when 8.1

What’s interesting, is I did. And it didn’t change so I just took the scrubber completely off line a few days ago. At first I just powered off the skimmer trying to isolate but per Randy’s article on pH I know I needed the skimmer going for o2. My scrubber was hook up in recirculating mode.

 

[Randy Holmes-Farley Verified Community Expert]

It's simple, Just program your apex to turn your skimmer off when you 're over 8.5, turn back on when 8.1

I wouldn't do that. Lack of aeration is why the pHwould be rising so much.

 

[Joedubyk]

I wouldn't do that. Lack of aeration is why the pHwould be rising so much.

oh that's interesting...

 

[Garf]

Bin some of your algae and reduce photoperiod until pH is where you want it. You can always increase it again if it gets a bit lower than you want.

Edit - I assume you’ve got it on a reverse lit cycle to the DT?