PH dropping, need help!

[Dryanimtt]

Fellow refers i need some help please. My PH keeps doing and can't get it up no matter what I do. Ph is now at 7.5 and corals are showing it. I have a brs co2 scrubber hooked to my skimmer. Alk at 8.7. Calc 450. Salinity 1.025. Phos 0.08. Plenty of surface agitation. I don't know what else to do.

 

[Garf]

Fellow refers i need some help please. My PH keeps doing and can't get it up no matter what I do. Ph is now at 7.5 and corals are showing it. I have a brs co2 scrubber hooked to my skimmer. Alk at 8.7. Calc 450. Salinity 1.025. Phos 0.08. Plenty of surface agitation. I don't know what else to do.

What are you using to test pH? If it’s a meter is it recently calibrated?

 

[Randy Holmes-Farley Verified Community Expert]

I too suspect measurement issues.

You can also try this aeration test:

pH And The Reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/

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.

 

[Dryanimtt]

I using a Milwaukee ph probe. I just calibrated it last week. And it matches what I get from the api ph test kit.

 

[Randy Holmes-Farley Verified Community Expert]

I using a Milwaukee ph probe. I just calibrated it last week. And it matches what I get from the api ph test kit.

I still suspect error. pH 7.5 is pretty extreme.

Try the aeration test above, if you can use outside air this time of year.

 

[Dryanimtt]

Is currently snowing and below freezing outside. How could I airate the tank more than I am now. I don't have an airstone either

 

[Garf]

Is currently snowing and below freezing outside. How could I airate the tank more than I am now. I don't have an airstone either

Test some new salt water if you’ve got some mixed.

 

[Randy Holmes-Farley Verified Community Expert]

Is currently snowing and below freezing outside. How could I airate the tank more than I am now. I don't have an airstone either

The aeration test is on a cup of water, not the tank. In any case, if it is snowing out it is not easy to do it well.

There is no instant cure aside from fresh air, but I truly expect it is not pH 7.5. I would order some new pH 7 and 10 calibration fluid and wait for that to arrive before doing much.

 

[Dryanimtt]

Yeah, I'll order some more calibration fluid. To be sure. Even though the drip ph kit i have also says the same. I also have a nano tank which confirmed ph test kit is accurate. Nano tank is 7.8

 

[Hersheyb]

since it's snowing, is your house pretty sealed up? are ppl inside the same room as the tank??

 

[Dryanimtt]

Yes and yes. But I did crash a window and run a line from my co2 scrubber which is connected to my skimmer and got a .1 increase to 7.6.

 

[homer1475]

100% measurement error.

You have a co2 scrubber and an airline outside to your skimmer.

Recalibrate your probe, throw out the API junk(yes API work, but they are not incredibly accurate), get a better test kit, then retest.

 

[Dryanimtt]

It's not a measurement error. I stuck the ph probe in my nano tank, reads 7.9. Api kit from nano water reads 7.8to 7.9 ish bed on color. Ph probe back in my big tank, 7.6, api kit reads about 7.6, nearly yellow in color where deeper purple is higher ph. In telling you something is amiss and I have no idea what it could be

 

[Randy Holmes-Farley Verified Community Expert]

It's not a measurement error. I stuck the ph probe in my nano tank, reads 7.9. Api kit from nano water reads 7.8to 7.9 ish bed on color. Ph probe back in my big tank, 7.6, api kit reads about 7.6, nearly yellow in color where deeper purple is higher ph. In telling you something is amiss and I have no idea what it could be

ONLY two things determine pH in seawater: alkalinity and carbon dioxide. Knowing those two would allow you to calculate the pH. Thus, if the tank is really that low in pH (do not ignore the fact that there are other aspects to measurement error than calibration; electrical interference is another) and another tank in the same air is not that low, then one (or both) of the two tanks is not aerating completely.

That's a reason to do the aeration test on water from both tanks using indoor air.

 

[prospervandale]

I know people have already said this but OPEN A WINDOW!!!. once I realized how tolerant humans were of co2(especially me because I’m an avid freediver/ spear fisherman) I started opening the window at least twice a day for AT LEAST 10 minutes. This will rip that PH above 8 if your surface agitation is as good as you said. good luck!

 

[esse]

ONLY two things determine pH in seawater: alkalinity and carbon dioxide. Knowing those two would allow you to calculate the pH. Thus, if the tank is really that low in pH (do not ignore the fact that there are other aspects to measurement error than calibration; electrical interference is another) and another tank in the same air is not that low, then one (or both) of the two tanks is not aerating completely.

That's a reason to do the aeration test on water from both tanks using indoor air.

I started looking into the pH of my tank, and the tank is measuring 7.75 with a calibrated meter(although just one from amazon), and I'm reading 8.4 dkh from a hanna alkalinity checker.

I tried to doing the aeration test with a cup of tank water & an airstone outside, and I'm only seeing the ph rise to 7.8 after a couple hours outside. Should I expect a greater increase?

I just calibrated the pH meter this morning, and I made sure to bring aerated sample back up to 25c when measuring pH. Would it be right to suspect that the hanna checker may be giving me an erroneous reading?

 

[Randy Holmes-Farley Verified Community Expert]

I started looking into the pH of my tank, and the tank is measuring 7.75 with a calibrated meter(although just one from amazon), and I'm reading 8.4 dkh from a hanna alkalinity checker.

I tried to doing the aeration test with a cup of tank water & an airstone outside, and I'm only seeing the ph rise to 7.8 after a couple hours outside. Should I expect a greater increase?

I just calibrated the pH meter this morning, and I made sure to bring aerated sample back up to 25c when measuring pH. Would it be right to suspect that the hanna checker may be giving me an erroneous reading?

Yes. That suggests the pH meter may be off somehow.

 

[esse]

Yes. That suggests the pH meter may be off somehow.

Does it also suggest that the numbers are off by a drastic amount? Is there anything else that could be throwing me off, beside user error?

According to the graph 3 in your article on low pH, at between 2 & 3 meq/l, the aeration at normal co2 could potentially raise it 0.3-0.4 pH, and I'm only seeing +0.05

 

[Randy Holmes-Farley Verified Community Expert]

pH 7.8 is OK in a reef.

If the alk is about 7 dKH, the pH should have risen to more than 8. It is possible that if it got very cold, that might be impacting the measurement. Is it cold outside?

 

[esse]

pH 7.8 is OK in a reef.

If the alk is about 7 dKH, the pH should have risen to more than 8. It is possible that if it got very cold, that might be impacting the measurement. Is it cold outside?

It’s not that cold, but I also brought the temp back up to the same temp by placing the cup in a bowl with hot water.

I suspect it is the pH meter. I found an old api kit this afternoon and retested. It seems to be showing closer to 8.2 for the outdoor sample, and a bigger difference between samples aerated outside, aerated inside, and from my two tanks.

Thanks again for your help!!