Alk/Ca/Mg/ph chemistry help needed.

[Pat613]

I have low pH, and calcium that fluctuates between 460 and 480 but I never dose.

Alk 10.5 - dose 1dkh red sea liquid alk daily, the salt has a dkh of 8. (I use the gap to dose more alk for the ph boost)

Calcium 460-480 (no dosing, it swings around at random)

Mg 1450 - dose 4ml red sea liquid mag daily (I find LPS “fluffier” with elevated mag)

pH 7.9 around the clock. Skimmer pulling through a co2 scrubber is making 0 difference. Additional surface agitation with open window, makes 0 difference.

20g IM Nuvo (4 fish, mixed corals)
Aquaforrest reef salt mixed to 1.025
Apex with trident for parameters (double checked occasionally with red sea tests)

My questions are, what is going on with the calcium? Why won’t the ph budge?

Any help greatly appreciated. Happy to provide any additional info. I’d like to get the ph up over 8.1, and understand what’s happening with the calcium as no uptake seems wrong if the alk is being deleted.

 

[TheDuude]

Are you having issues with the tank?

Calcium fluctuating a bit is normal. I also would not be concerned with a PH of 7.9.

 

[Pat613]

The tank is looking fine, just trying to understand why nothing moves the ph. Firgured the co2 scrubber, fuge, and fresh air/low co2 should raise the ph with the alk at 10.5.

I've read this @Randy Holmes-Farley article back to front trying to figure it out http://www.reefkeeping.com/issues/2004-09/rhf/

 

[Pat613]

Hmm, my Hanna ph tster says 8.3. I'll recalibrate my Apex probe tonight. I'd calibrated it 6 weeks ago and assumed it'd still be close.

 

[TheDuude]

pH probes do tend to wander over time. I usually calibrate mine every 6 months or so. If your fish and corals are doing good and your happy with growth and coloration I would not chase the numbers.

It was hard for me at first as well but I think something you always have to keep in mind is that no two reef tanks are alike. Stability is much more important than having the exact number that people are shooting for at that time.

If your noticing things like “lps looks fluffier with elevated mag" then your already more tuned in to your tank than many. I personally love that style of reefing.

 

[Pat613]

pH probes do tend to wander over time. I usually calibrate mine every 6 months or so. If your fish and corals are doing good and your happy with growth and coloration I would not chase the numbers.

It was hard for me at first as well but I think something you always have to keep in mind is that no two reef tanks are alike. Stability is much more important than having the exact number that people are shooting for at that time.

If your noticing things like “lps looks fluffier with elevated mag" then your already more tuned in to your tank than many. I personally love that style of reefing.

Thanks! My only gripe is that growth has been slow. So if pH is a limiting factor, I just want to rule it out as a hurdle. I too am a fan of just generally being in tune with the tank .

 

[Pat613]

Annoyingly, after calibrating the tester, 7.9. I figured if one pH probe is off, better to calibrate both. The tester being more convenient to calibrate, was done first. Still going to calibrate the Apex to be super-duper sure, but I imagine it's very close, it matches a freshly calibrated tester.

Which brings me back to, why can't I get the pH up?

 

[Pat613]

Aeration test is proving effective, latest bag of scrubber media must be trash. Go ice-cap...

 

[Pat613]

Are you having issues with the tank?

Calcium fluctuating a bit is normal. I also would not be concerned with a PH of 7.9.

But shouldn't I have to dose it at some point? I haven't dosed any, and it never dips below 460. Alk I dose daily as it depletes ~1dkh/day.

 

[Randy Holmes-Farley]

But shouldn't I have to dose it at some point? I haven't dosed any, and it never dips below 460. Alk I dose daily as it depletes ~1dkh/day.

1 dKH per day would deplete calcium at about 7 ppm per day if it is all used for calcification.

Water changes might keep the calcium up.

 

[Pat613]

That makes sense, thank you so much! Nice to know there's a general ratio.

 

[Randy Holmes-Farley]

That makes sense, thank you so much! Nice to know there's a general ratio.

You're welcome.

This article has much more info on this topic:

When Do Calcium and Alkalinity Demand Not Exactly Balance? by Randy Holmes-Farley - Reefkeeping.com