pH fluctuation. Yet another post...

[MexiReefer]

Do younguys belive this is a problem? Normally my pH ranges from 8.2 to 8.6 daily.
It is a 25gal system, daily dosage of alk and calcium. Refugium with chaeto with 12 hours light cycle opposed to tank lights

any comment will be appreciated

 

[GillMeister]

There's something going on with your probe. Clean it or replace it but first check to make sure the cable isn't picking up interference from a power cord.

 

[Randy Holmes-Farley]

Have you calibrated it recently? IMO, the pH is probably not that high. If it is, more aeration will reduce it.

 

[GillMeister]

One other thing to consider. Are you dosing near the pH probe? I don't think that's the problem but it's not impossible.

 

[MexiReefer]

Thanks for the responses. I recalibrated just now. Will post results.

i donot dose near the probe. Normally dose in the tank close to the wavemakers and the probes are in the sump.
Thanks again

 

[MexiReefer]

I recalibrated @Randy Holmes-Farley and still have a 8.75 pH reading. See below.

My question is if this high pH is the cause of having some sad corals in my tank: fully retracted Micromusas, bleaching favias and melting zoas. other inhabitants seems undisturbed like clams, anemone bubble corals, etc.

thanks for any input and happy to add information

 

[arking_mark]

So, I don't think your pH reading is correct unless you are over-dosing a high-pH supplement/additive or keeping your alkalinity very high or heavy CO2 scrubbing.

The fact that you are seeing a 0.3 day/night swing is typical for many reefers. Although it probably shouldn't swing that much with a reverse lighting schedule refugium.

What additives are you using?
How are you aerating your tank?
Have you tried your probe on freshly mixed artificial salt water to see it's pH?

 

[GillMeister]

You recalibrated it but did you check for interference? If this was an effect from dosing I have to believe it wouldn't be consistently in the pH range your Apex shows it. Did you verify pH with a test kit?

You're smart enough to realize if something looks wrong, it must be wrong. Otherwise you wouldn't be asking the questions you're asking. Something has got to be wrong with the pH reading.

 

[MexiReefer]

Thanks for all the input. I ordered a pH test kit to double check the reading.

Later today will do a airation test and also use the probe to test fresh saltwater.

Alk is consitently around 8.0 - 8.3
Ca 420
Mg 1,340

I daily dose 2ppm of Ca and 0.4 of Alk by adding Ca additive (redsea) and Bakind Soda (Randy's recipie)

Ps- @GillMeister quotes "You're smart enough to realize" <-- I would like to think I am smart, but there is a lot of evidence against that thought

 

[MexiReefer]

Hi Guys, so after recalibrating, checking for interference and double checking with a salifert test kit, the PH reading seams to be accurate.

I areated the tank for over a week with an air stone (it was a rather small pump, but it was what I had on hand), and it did no difference what so ever.


Where to go from here?

 

[MexiReefer]

 

[arking_mark]

It may be possible that your photosynthetic organisms are consuming your tanks CO2 (which directly impacts your pH). Try turning off your refugium lights for a night. Also, as Randy mentioned, more aeration.

 

[Randy Holmes-Farley]

Try the aeration test with indoor air. An airstone in a tank is not generally going to solve an aeration issue.

The pH MUST drop in the aeration test unless the alk is above 12 dKH. If it does not, the pH measurement is inaccurate. If it does, then more aeration in the tank will lower the pH.

pH and the Reef Aquarium - REEFEDITION

by Randy Holmes-Farley For many aquarists, pH is not something that they have much experience with aside from their aquarium. For many, pH is almost a black box measurement: something to be considered, but whose physical meaning makes little sense to them. This article will Read more here...

www.reefedition.com

The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.

 

[MexiReefer]

Thanks Randy. If the airstone is not enough to aerate the tank, an airstone is not enough, then how am I supposed to do it? The surface of the tank is heavily disturbed by the wavemakers, plus the filtersock, plus a UV filter outlet that also "splashes" into the sump. How ese can I intrduce ambient CO2 into the tank?? :/

 

[MexiReefer]

Added 10ml of white vinegar, because why not. let´s experiment. pH dropped from 8.66 to 8.58. Planning to add 25ml in total, so I'll wait a couple of hours and complete the dosing, while monitoring the pH.

 

[arking_mark]

Thanks Randy. If the airstone is not enough to aerate the tank, an airstone is not enough, then how am I supposed to do it? The surface of the tank is heavily disturbed by the wavemakers, plus the filtersock, plus a UV filter outlet that also "splashes" into the sump. How ese can I intrduce ambient CO2 into the tank?? :/

Try not lighting you refugium tonight.

 

[MexiReefer]

Try not lighting you refugium tonight.

Turned off the refugium, made a difference at the night pH reading but still goes over the top dutimg day time.

 

[arking_mark]

Turned off the refugium, made a difference at the night pH reading but still goes over the top dutimg day time.

So you identified the issue...lots of photosynthesis.

 

[MexiReefer]

So you identified the issue...lots of photosynthesis.

But it is something unavoidable, am I right?

 

[arking_mark]

But it is something unavoidable, am I right?

Lower your lighting periods/intensity, get Alk to mid 7s, and/or add a skimmer if you don't have one.

However, I'm not sold on the measurements being accurate and would only do one small change at a time.