PH drop in mature tank....

[Shevlin77]

All, Been reefing for 17 years. My current tank has been running for 7 years in the same place in the house. PH has always been between 8.1 and 8.4. I do not run a skimmer because my tank is SPS dominate and runs at ULN. Last week all of a sudden it dropped all the way down to 7.3 overnight. Went back up the next day and now runs between 7.7 and 8. I validated it with another PH tester which is matching up with the trident probe. This was after a water change that dropped my Mag from 1350 down to 1260 or so. Which I have dosed back up. Other than the water change using the same salt for years, nothing has changed in my house or in my maintenance or dosing routine. Nothing at all. I bought a CO2 monitor and it's showing 0 in the room where the tank is. When I open the door into the room to the outside it jumps up around .1 but not enough. Key parameters are normal per an ICP test outside of low Fluorine, Barium and Molybdenum (sp?) being low which I am dosing back up with RM. Did noticed that the aluminum level in the tank...which is always present around 7-9 ug/l over the last few years, jumped up to 11ug/l on my last ICP test. But that's still pretty low and should not effect PH from what I have read. So, any thoughts on what could have suddenly changed to make the PH drop after running so stable for 7 years?

 

[Randy Holmes-Farley]

The downward spike might be been error/interference if the check you did was after it was back up.

There are no chemicals in the tank that noticeably matter for pH except alkalinity, and how you add it.

How do you add alk?

 

[Shevlin77]

The downward spike might be been error/interference if the check you did was after it was back up.

There are no chemicals in the tank that noticeably matter for pH except alkalinity, and how you add it.

How do you add alk?

Thanks for the reply. I use the trident DOS and use ME Corals Alk liquid. Been dosing between 80-90ml daily for years. I added a CO2 scrubber and that helped.... but I'm just at a loss as to why it would change suddently after all these years running the exact same way. The most confused I've been in the 17 years in the hobby lol.

 

[Randy Holmes-Farley]

Thanks for the reply. I use the trident DOS and use ME Corals Alk liquid. Been dosing between 80-90ml daily for years.

OK, so it wasn't an errent release of CO2 from a reactor.

Unless you had some sort of high CO2 event at your home that day (lots of people or lots of gas stove cooking), I'd lead toward testing issues.

I'd recalibrate now in any case.

 

[Shevlin77]

OK, so it wasn't an errent release of CO2 from a reactor.

Unless you had some sort of high CO2 event at your home that day (lots of people or lots of gas stove cooking), I'd lead toward testing issues.

I'd recalibrate now in any case.

Thanks. We only use gas to cook but never much for our family of 4. So, I did recalibrate, and it said the calibration was successful per the trident. But can I trust that? Wonder if the probe can just finally go bad. bought an API manual strip test. Which kinda matched up with the trident probe but i'm so bad with reading colors who knows for sure.

 

[Randy Holmes-Farley]

So I did recalibrate, and it said the calibration was successful per the trident. But can i trust that?

Does it read the two calibration fluids correctly, especially the high one (typically pH 10)?

 

[Shevlin77]

Does it read the two calibration fluids correctly, especially the high one (typically pH 10)?

Yes, it did. When the calibration process showed complete/success it was showing 10 on the apex fusion app before I put the probe back in the tank.

 

[Randy Holmes-Farley]

Yes, it did. When the calibration process showed complete/success it was showing 10 on the apex fusion app before I put the probe back in the tank.

OK. What is the pH now?

This test may help determine if elevated CO2 is an issue:

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.

 

[Shevlin77]

OK. What is the pH now?

This test may help determine if elevated CO2 is an issue:

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.

It's running between 8 and 8.2 now that I have the icecap co2 scrubber on it. I will try this test. Thanks for posting. the CO2 monitor I purchased shows 0ppm for co2 in the room where the tank is but could not hurt to try this. Would rather not have to deal with a scrubber long term given this was not an issue for so many years. Thanks for all your help.

 

[14 foot reef]

It's running between 8 and 8.2 now that I have the icecap co2 scrubber on it. I will try this test. Thanks for posting. the CO2 monitor I purchased shows 0ppm for co2 in the room where the tank is but could not hurt to try this.

cO2 can not be 0.00

Outside air is around 450ish, Inside would be above that by some small amount, or large amount if lots of people and or pets and gas cooking as Randy mentioned.

Carbon Dioxide Levels Chart

Our carbon dioxide (CO2) levels chart shows the increasing danger of elevated levels of CO2 in enclosed spaces.

www.co2meter.com

 

[Miami Reef]

When I read the first post, my mind instantly wanted to correct the “0 ppm” CO2 reading.

Outside air is about 400ppm. Inside air is usually higher from respiration and gas cooking.

 

[Shevlin77]

When I read the first post, my mind instantly wanted to correct the “0 ppm” CO2 reading.

Outside air is about 400ppm. Inside air is usually higher from respiration and gas cooking.

It’s what the meter I purchsed is showing. It starts out at around 167ppm when you start the test it then goes down to zero when it finishes. .

May not be using it correctly or could be broken.

 

[Miami Reef]

It’s what the meter I purchsed is showing. It starts out at around 167ppm when you start the test it then goes down to zero when it finishes. .

May not be using it correctly or could be broken.

That’s how you know the meter is inaccurate.