Low PH

[CoxMarineCreations]

Hello everyone,

I’m slightly hesitant to post here since I’m running a small hobby business, but I figure we all need help sometimes and I’m sure even the big guys ask for advice now and then.

Anyways, why would my pH be low?

I have great flow and surface agitation, a protein skimmer, and all the things. The window in my fish room has even been open 24/7 now that it’s summer.

Current parameters:

• pH: 7.9 (Hanna Marine pH Tester) tested around noon.

• Alk: 9.3 dKH

• Phosphate: 0.39 ppm

• Magnesium: 1320 ppm

• Salinity: 1.025 (Hanna Salinity Checker)

• Temperature: 78.4°F

What am I missing?

Is there something obvious I should be looking at? At this point I’m wondering if I’m dealing with excess CO₂ somewhere or something else entirely.

Thanks in advance!

 

[X-37B]

First thing I would do is get another ph meter and probe. Calibrate both and compare to make sure its 7.9
What is the day night swing?
What do you dose?
I had low night ph 7.6 and day 8.0
I dose kalk 24/7 now and have a night low of 7.9 and a day ph of 8.2-8.3.

 

[Randy Holmes-Farley Verified Community Expert]

Your pH is ok, but pH is determined mathematically by the CO2 level in the water and the alkalinity.

CO2 in the water is often driven up by CO2 in the air in contact with the water.

 

[Channas]

Try test it in the evening as Well to see if it’s any higher, also do you keep a lid? What are your other params? Low alk can influence ph as many other things but the most common ones i belive are if there is a lid present, low alk or undufficient skimmer but keep in mind that ph drops at night and is atThe lowest point just when the lights starts and at it’s highest point before lights go out. There could be a contaminent present as Well especially if you use citric or myriadic acid to clean pumps etc, any Left over acid will lower ph

 

[CoxMarineCreations]

First thing I would do is get another ph meter and probe. Calibrate both and compare to make sure its 7.9
What is the day night swing?
What do you dose?
I had low night ph 7.6 and day 8.0
I dose kalk 24/7 now and have a night low of 7.9 and a day ph of 8.2-8.3.

So I’m not sure the night swing but day time I used to be stable at 8.3-8.4

I dose Reef Carbonate 10.5ml daily throughout the day.

 

[Peer.Boerner]

Hello everyone,

I’m slightly hesitant to post here since I’m running a small hobby business, but I figure we all need help sometimes and I’m sure even the big guys ask for advice now and then.

Anyways, why would my pH be low?

I have great flow and surface agitation, a protein skimmer, and all the things. The window in my fish room has even been open 24/7 now that it’s summer.

Current parameters:

• pH: 7.9 (Hanna Marine pH Tester) tested around noon.

• Alk: 9.3 dKH

• Phosphate: 0.39 ppm

• Magnesium: 1320 ppm

• Salinity: 1.025 (Hanna Salinity Checker)

• Temperature: 78.4°F

What am I missing?

Is there something obvious I should be looking at? At this point I’m wondering if I’m dealing with excess CO₂ somewhere or something else entirely.

Thanks in advance!

I’m no expert but I had a similar issue. Ran a 1/2” pvc pipe to out side air and used that to feed the skimmer. PH stayed at 8.0 no matter what. Then I decided to recalibrate my pH probe again. I had recalibrated 2 weeks prior but thought maybe I made a mistake. Sure enough, the probe was not calibrated properly and now reading 8.3 peak during the day. Then I added back my co2 scrubber and that took my daytime ph to 8.45. I then moved Kalk dosing to only run at night, starting when the ph would drop after the lights turned off. Now my low is 8.1 and my high 8.45. You may want to clean and recalibrate your probe. Also be sure to gently clean the probe. Hope you find the solution!

 

[vetteguy53081]

Hello everyone,

I’m slightly hesitant to post here since I’m running a small hobby business, but I figure we all need help sometimes and I’m sure even the big guys ask for advice now and then.

Anyways, why would my pH be low?

I have great flow and surface agitation, a protein skimmer, and all the things. The window in my fish room has even been open 24/7 now that it’s summer.

Current parameters:

• pH: 7.9 (Hanna Marine pH Tester) tested around noon.

• Alk: 9.3 dKH

• Phosphate: 0.39 ppm

• Magnesium: 1320 ppm

• Salinity: 1.025 (Hanna Salinity Checker)

• Temperature: 78.4°F

What am I missing?

Is there something obvious I should be looking at? At this point I’m wondering if I’m dealing with excess CO₂ somewhere or something else entirely.

Thanks in advance!

This ph level would be acceptable especially if stable/steady

 

[Alexander1312]

Essential to understand your ambient CO2. Without a CO2 meter, this will not be helpful. Once this is ruled out, other steps can be considered.

Also, if you test PH not continously, I would test it right at the end of the light cycle, and just before the light cycle starts. This way you understand the fluctuation which tells you if your buffering works within acceptable levels.

For example, even if you have 7.8 at the beginning, and 8.1+ at the end, you will still be fine.

 

[Randy Holmes-Farley Verified Community Expert]

I personally would not bother to get a CO2 meter. if one wants to know if ambient CO2 is an issue without buying a new device, this test will tell:

https://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.

 

[X-37B]

If you want an inexpensive co2 monitor this works well. I have one in my fish room. Co2 goes down if the sliding door is open.
Average co2 in the room with door closed is 440.
Most frags cost more than this meter, lol.

 

[Randy Holmes-Farley Verified Community Expert]

I would just point out that the meter reading does not tell the whole story. The aeration test will.

For example, if the pH reading is low and the CO2 is elevated, is the pH low due to inadequate aeration, or just the high CO2, or both?