How is ph so low?

bubbaque · Feb 25, 2017

I received a new Apex today and got every going with it. I calibrated the probes according to the instructions and I get a ph reading of 7.5. I am just not sure how it is so low when I have a hose from skimmer to the outside for fresh air, dose kalk through my ATO and run a light over my fuge to help with ph. With those three things it doesn't seem logical to me to have my ph so low. What do you think?

Diesel · Feb 25, 2017

Any idea where you ALK sit at?
Test also your new salt mix

bubbaque · Feb 25, 2017

Alk is 8.5. Will test new salt tomorrow

bubbaque · Feb 25, 2017

I guess I should also ask how long the calibration fluid is good for or how many times can I use it. I had to try and calibrate the probes probably three times today over 5 hours because apex fusion wouldn't accept the calibration when I would try to save. It kept making me log back in every time. If the fluid is only good for one use then it might be why it's not reading accurately.

Edit: never mind I remember sticking the probes in the solution and it reading 7 and 10 ph in each of the correct fluids.

Diesel · Feb 25, 2017

I use the APEX screen to calibrate my PH Probe.
Not sure if you can do it through your fusion.
If you read through your APEX manual it says always calibrate through your apex screen or drop a CAT 5 cable between the APEX and laptop or computer device.

Randy Holmes-Farley · Feb 25, 2017

You can try this test to see if the result is real and what the cause is:

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.

kasik64 · Feb 25, 2017

Randy Holmes-Farley said:
You can try this test to see if the result is real and what the cause is:

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.

Thanks for the link. Has helped me. My tank has a low pH that just won't work with me. Trying a small fan today, next would be kalkwasser.

bubbaque · Feb 25, 2017

@Diesel what do you mean the Apex screen? The new apex doesn't come with a screen, so I use the Neptune apex app on my iPad . I recalibrated this morning and now get a reading of 7.24

Randy Holmes-Farley · Feb 25, 2017

bubbaque said:
@Diesel what do you mean the Apex screen? The new apex doesn't come with a screen, so I use the Neptune apex app on my iPad . I recalibrated this morning and now get a reading of 7.24

That's almost certainly not accurate, so something is wrong with the test.

Calibration and measurement is temperature sensitive, so be sure to follow the directions that relate to temp.

Also, what calibration buffers did you use?

bubbaque · Feb 25, 2017

Randy Holmes-Farley said:
That's almost certainly not accurate, so something is wrong with the test.

Calibration and measurement is temperature sensitive, so be sure to follow the directions that relate to temp.

Also, what calibration buffers did you use?

I just received the apex yesterday and used the fluids it came with.

The instructions I followed were through the "getting started" from the Neptune apex site and didn't see anything about temp or not calibrating a certain way. I just click auto calibrate and follow the instructions, which are, stick the probe in 7.0 solution, click next and then stick it in the 10 solution. I also whipped the outside of the probe off before sticking it in the next solution and tried to blow the fluid out of the tip of it.

Randy Holmes-Farley · Feb 25, 2017

Temperature impacts pH measurement, so if the fluids are not close to the tank temp (or measured and corrected by the device), calibration will be imperfect.

bubbaque · Feb 25, 2017

Thanks, going to go pick up new fluid now and will float the bags in the sump

Randy Holmes-Farley · Feb 25, 2017

Sounds good.

Let us know what you find.

bubbaque · Feb 25, 2017

I recalibrated and get 7.68 now which I feel is still low with fresh air into the skimmer and kalk dosing.

bubbaque · Feb 25, 2017

What's weird is the very first time I calibrated I got 7.9 but recalibrated after a few hours to make sure it was correct. Now I get different reading with each calibration.

Randy Holmes-Farley · Feb 25, 2017

Just make sure you can read the calibration fluids OK after calibration. pH 7.6 and up is within the range that folks can sometimes get, but below that, not so much.

bubbaque · Feb 26, 2017

Thanks, I just still feel something is off with doing all the things people say to do when ph is low, hose to skimmer, kalk, and refugium, only still to have a low ph.

I found a thread where it said the offset in the apex fusion for the ph probe should be at a certain number and mine is way off. So I followed instructions to reset it, so tomorrow I will go buy new fluid and try again.