High ph

[Sharkey18]

Reasons for high pH? 

 

pH in the am is around 8.62, by evening it is 8.68.

Kh is at 8.45

 

I am not dosing anything, running a skimmer.

 

Checked pH probe in pH10 test solution and it was accurate.

 

Ideas?    

[Origami]

Did you check a second reference - like pH 7 calibration fluid, too?

 

This is unusual. The probe's not located near there an alkalinity additive (kalk or sodium carbonate) is dosed, is it?

 

Try the aeration test, aerating it with fresh air and see if the pH falls. You may have an uncommon case of low CO2.
 

You've not been using any sort of pH buffer, have you?

[Rosco's Reefs]

what is the aeration test? take it out of the water?

[Origami]

what is the aeration test? take it out of the water?

Take a cup or two of water out and aerate it in fresh air for a half hour. It attempts to bring the dissolved gasses into equilibrium with the atmosphere. In cases of low pH, it blows off CO2. In a case like this, where there's a possibility of CO2 deficiency, it adds CO2 to lower the pH. In this case, the suggestion was made as a diagnostic tool to see if low CO2 is the cause of Laura's high pH.

 

Sent from my Rezound on Tachyon using Tapatalk

 

 

[L8 2 RISE]

I like Tom's suggestion, haven't heard that one before.  

 

Not to hijack, but because it's not often encountered, what are the problems associated with a high pH?

[L8 2 RISE]

Just found this great article: http://reefkeeping.com/issues/2005-03/rhf/

[wade]

I've seen araganite turn into cement.  Its not a good thing.  Not to mention you get precipitation of a lot of things.

[Sharkey18]

So I realized I am already running the test that Origami suggested. 

 

I am hatching baby brine shrimp for the baby cardinals. I basically take 800ml of tank water, drop in some eggs and aerate. 

Set up a new batch last night. Tested this morning. 

 

pH of the brine shrimp water is 8.19  I doubt the eggs had much of an effect on the pH. But I will repeat the test tonight with just the water. 

 

So basically, my water in NOT getting enough CO2 and like Origami said I have "an unusual case of low CO2". 

 

This surprises me since I though that running a skimmer would provide more than enough aeration to keep the water and the air at equilibrium. So how do I aerate 400g of water? I don't think an airstone is going to do it….. 

[wade]

It is very unusual.  A large air stone (or the wooden blocks) in the main display would certainly do it.  But it'd be both ugly and messy.

 

Generally, strong water flow inside the tank will do it.  Aim a powerhead or return upward to cause some amount of visible upwelling on the surface of the tank.  One thing to check on is airflow inside your hood too.  If it is fairly well sealed, it'll slow air exchange.

 

If you have a controller, you can set it to turn on a venturi style powerhead when pH goes above a certain mark (like 8.3).  You can use a short piece of airline tubing above the water to run air in - as a fairly simple fix. Or do the same thing with a fan aimed at the surface of the tank - turn on when pH rises. Turn off when it is in a good range.

Edited December 18, 2013 by wade

[Sharkey18]

Thanks Wade. 

 

I am going to add some surface agitation today. I have excellent flow in the tank, but none of it breaks the surface.

 

I don't have a hood and the entire tank and sump are open to the air. Everything is in the fish room, and I usually keep that door closed… perhaps that is contributing. 

 

I do have a window cracked in there or else the humidity gets too high. 

 

I like the idea of a venturi linked to the controller…. 

 

Is there a way to measure the CO2 of the air?  Perhaps there is not enough CO2 in my house. Maybe I am suffering from a constant state of O2 narcosis. That would explain a lot……  

[wade]

O2 narcosis... LOL.  You'd be able to run a 5k without breaking a sweat.   So long as you didn't leave your fish room.

 

I don't know of a good way to measure CO2, but I'd think that watching your pH in the tank would work - as it is an indirect indicator. 

 

BTW- high rates of photosynthesis can consume a good bit of CO2, which can repress in tank concentrations. Surface mixing should fix a lot of that though.  I've not seen many (if any?) cases of it not returning to normal at night when the process reverses though.

[YHSublime]

If you don't have enough surface agitation, you could always jump in on one of the gb's for th WP-40's. 2 of those on W1 will agitate your tanks surface all day long!

[Origami]

So I realized I am already running the test that Origami suggested. 

 

I am hatching baby brine shrimp for the baby cardinals. I basically take 800ml of tank water, drop in some eggs and aerate. 

Set up a new batch last night. Tested this morning. 

 

pH of the brine shrimp water is 8.19  I doubt the eggs had much of an effect on the pH. But I will repeat the test tonight with just the water. 

 

So basically, my water in NOT getting enough CO2 and like Origami said I have "an unusual case of low CO2". 

 

This surprises me since I though that running a skimmer would provide more than enough aeration to keep the water and the air at equilibrium. So how do I aerate 400g of water? I don't think an airstone is going to do it….. 

Throw a party. Add respiring organisms like fish. Remove photosynthesizing organisms like macro. 

 

If you're dosing two-part and using the recipe that calls for baked baking soda (sodium carbonate) for the alkalinity part, then switch to the baking soda (sodium bicarbonate) part.

 

You could add a calcium reactor - even without media and use it to drop the pH when it gets too high. Or a  mineral acid drip (maybe that's a bit risky).

[Sharkey18]

Before I left for work I pointed one of my returns toward the surface to get a lot of air mixing w water and came home to a HIGHER pH.

 

Now at 8.72!

 

Opening windows…. 

[Sharkey18]

Update: 

 

Tap water pH= 8.3

RODI output pH= >9! 

 

What could be happening in my RODI to cause high pH? 

[Origami]

pH of RO/DI is easily shifted, Laura. Don't trust tests on pure water.

 

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[mr.x-ray]

Update:

 

Tap water pH= 8.3

RODI output pH= >9!

 

What could be happening in my RODI to cause high pH?

As Tom said. pH will not read correctly in tap or RO water once calibrated in 7&10. My RO/DI reads 10.5

I'm really suspect of a calibration shift in your probe. Mine has shifted .4 in a matter of days. From 8.1 jump to >8.5! Some probes will go crazy prior to dying also. I would go through the whole calibration steps with 7 & 10 again if you haven't already.

Have you tested with a test kit?