PH high since adding refugium

[wetone]

My PH was always at a stable 8.2. Two weeks ago I added a refugium and the caulerpa is growing great. I have the fuge lights on for 12 hrs opposit the main tank. The PH is around 8.36 during the end of the main tank lighting period. The tank is at 8.58 this morning about 10 hrs after main lights go off and fuge lights come on.

I also have been adding Kent turbo calc daily to bring my CA up. It was around 330, now up to 400.

All corals and fish seem happy
What could be causing this?....should I be concerned?...how do I lower it?

 

[ChrisRD]

How are you testing pH? Can you describe your system in more detail?

I suppose it's possible for pH to rise a bit from the lowered CO2 levels (due to all the additional macro growth), but it doesn't seem likely (at least to me) that it could get THAT high.

My first thought is that there's something up with your pH test kit/meter. Having a high pH in the morning is the opposite of what I'd expect to see (unless your fuge is larger than your display tank and has stronger lighting)...

 

[wetone]

DKH = 10.1
ALK = 3.71
SG = 10.23
CA = 375-400 (having trouble moving this up !!)
NO3 = 0
PO4 = 0 (although still battling small algae problem, hopefully the fuge will be final step to eliminate this)

My tank is a 75G with 2 250W MH and 2 110W vho actinics. The 25G fuge is lit by LOA 65W 6500K.
I have taken a test with a Salifert kit and the PH shows around 8.3. I have a PH monitor that is fluctuating betwewen the 8.3 and 8.6. I will need to get some calibration solution and check it out

 

[Wrassman]

This may seem like a silly question, but have you checked your magnesium levels? You may have an ionic balance problem, particularly if you have been using turbo calc on a daily basis. Have you also been using Superbuffer on a daily basis? Have you ever tested your magnesium levels?

If the answer is no, I would advise taking some water to your LFS and get him/her to run Ca, Alk, Mag, pH. This will give you a baseline from which to operate. You want your Mag levels around 1400 (at least, that's where I try to keep mine).

HTH

 

[ChrisRD]

I have taken a test with a Salifert kit and the PH shows around 8.3. I have a PH monitor that is fluctuating betwewen the 8.3 and 8.6. I will need to get some calibration solution and check it out

Sounds like something might be up with your probe. I'd use the kit to check the water at the same time you are getting the high reading on the probe to verify.

Unless you are dripping kalkwasser overnight (which BTW could help your algae problem) I don't see why your pH would climb that much during the night.

BTW, I'm not discounting Wrassman's post - I just don't know what effect low Magnesium levels would have on your pH (although it can certainly cause a problem with maintaining Calcium levels).

 

[wetone]

I do drip kalk at about 1.5G per day as an evaporation fill.
I never have tested the MAG, but I guess I should, this could also be a problem with low CA even though I keep adding turbo CA. I do add buffer to keep ALK and DKH up

 

[Wrassman]

I never have tested the MAG, but I guess I should, this could also be a problem with low CA even though I keep adding turbo CA. I do add buffer to keep ALK and DKH up

As I stated, this can be indicative of an ionic imbalance, when you keep adding Ca, but it is still low, and you add buffer to keep alk and dkh up, and now the pH is out of whack. All symptoms of low magnesium.

Take your water to an LFS for a baseline test and start adding your supplements from there.

HTH