Adding skimmer to raise PH?

[theishkid]

My PH is running between 7.7 - 7.89 throughout the day (recently calibrated APEX probe and confirmed by Hanna Master Checker). I have pretty low nutrients so even though I bought a skimmer, I haven't added it to the tank yet. Would adding a skimmer (not with an airline outside) help bump up the PH at all? Would it even be worth it if there aren't enough nutrients in the tank to strip out even more?

For extra context...
150 Gallon Display
50 Gallon Sump
Salinity 1.025
Temp 77
Alk 9
Ca 430
Mag 1310
Phosphate .04
Nitrate 3

I'm dosing All for Reef by hand at night before bed.
I add some Brightwell NeoNitro to raise Nitrates and some Coral Aminos every couple of days.
I have a refugium on reverse lighting cycle with Chaeto that grows pretty well.

 

[theishkid]

My PH is running between 7.7 - 7.89 throughout the day (recently calibrated APEX probe and confirmed by Hanna Master Checker). I have pretty low nutrients so even though I bought a skimmer, I haven't added it to the tank yet. Would adding a skimmer (not with an airline outside) help bump up the PH at all? Would it even be worth it if there aren't enough nutrients in the tank to strip out even more?

For extra context...
150 Gallon Display
50 Gallon Sump
Salinity 1.025
Temp 77
Alk 9
Ca 430
Mag 1310
Phosphate .04
Nitrate 3

I'm dosing All for Reef by hand at night before bed.
I add some Brightwell NeoNitro to raise Nitrates and some Coral Aminos every couple of days.
I have a refugium on reverse lighting cycle with Chaeto that grows pretty well.

Slightly more context I forgot to mention...
The house is about 3000 sq ft built a couple of years ago and it is sealed pretty well with foam insulation.
We added some air recyclers to bring in fresh air last year after we were getting 70% humidity and poor air quality warnings on the thermostats and they fixed the problem.

I don't think the tank is a CO2 problem because I've gone all day having the windows open in the house and it might bump it up to 7.95 at the most. It is just me and my wife and we are gone most of the day working except for a few hours at night and on the weekends.

According to my AvidAqua Insight the CO2 in our small media room we spend most of our time in might get to 850 but never more than that. Most of the time it's in the 700 range. But that room is small and away from the tank.

 

[Randy Holmes-Farley]

Skimmers can raise or lower pH. Try aerating a cup of tank water for an hour and see what that does for pH.

If the CO2 level you quote is accurate, aeration of normal seawater will give a pH around 7.9.

 

[rishma]

 

[theishkid]

Skimmers can raise or lower pH. Try aerating a cup of tank water for an hour and see what that does for pH.

If the CO2 level you quote is accurate, aeration of normal seawater will give a pH around 7.9.

Start of test - Tankwater
Apex was 7.84

End of test -
Apex in aerated cup was 7.72
Apex in tank at end of test was 7.83

So I ended up lowering my PH a little bit.

 

[HARDY CORALS]

Bump for info. I too battle low ph in my tank. I added skimmer, small bump. Added co2 scrubber to skimmer small bump. Switch dosing to kalkwasser at night for now. Small bump.
In the beginning my nightly lows were 7.5 and daytime highs around 7.75.
After all these changes I am at nightly low on 7.9 and daily high to 8.05 at best.

 

[rishma]

Start of test - Tankwater
Apex was 7.84

End of test -
Apex in aerated cup was 7.72
Apex in tank at end of test was 7.83

So I ended up lowering my PH a little bit.

Is that aerated outdoors or indoors?

 

[theishkid]

Is that aerated outdoors or indoors?

Indoors about 10 feet from tank (so same air the tank is getting).

 

[rishma]

Indoors about 10 feet from tank (so same air the tank is getting).

Ok. What that probably tells you is CO2 in the tank was a little less than equilibrium with the air likely due to photosynthesis consuming CO2. Pretty normal.

If you repeat the experiment with outdoor air you will probably find pH goes up, though if the water temperature drops during the experiment it also increases the pH measurement

 

[Randy Holmes-Farley]

Start of test - Tankwater
Apex was 7.84

End of test -
Apex in aerated cup was 7.72
Apex in tank at end of test was 7.83

So I ended up lowering my PH a little bit.

High CO2 in the air or inaccurate pH calibration.

Assuming the high CO2 explanation, a skimmer won't help unless you use a CO2 scrubber on the air inlet, or send outside air to the skimmer inlet

 

[Randy Holmes-Farley]

Nice. Did you make these graphs?

 

[theishkid]

High CO2 in the air or inaccurate pH calibration.

Assuming the high CO2 explanation, a skimmer won't help unless you use a CO2 scrubber on the air inlet, or send outside air to the skimmer inlet

I ran a CO2 scrubber on an older tank but got tired of replacing media so often... are there any studies to the effectiveness of bringing in outside air if you have to go really long distance? I'd have to send a hose up my wall and over to a soffit in the attic. It's very doable but probably 40 - 50 ft total with a few bends or curves.

 

[Randy Holmes-Farley]

I ran a CO2 scrubber on an older tank but got tired of replacing media so often... are there any studies to the effectiveness of bringing in outside air if you have to go really long distance? I'd have to send a hose up my wall and over to a soffit in the attic. It's very doable but probably 40 - 50 ft total with a few bends or curves.

That's a complicated question that I would not rely on a "study" of it, but seeing what others have done can help. A cheap air pump outside could overcome the pressure drop. The attic itself might be a fine place to get air, depending on its air flow.

 

[rishma]

Nice. Did you make these graphs?

Yes. I find it’s a useful way to look at it. You helped me last year with the dissociation constant

 

[theishkid]

That's a complicated question that I would not rely on a "study" of it, but seeing what others have done can help. A cheap air pump outside could overcome the pressure drop. The attic itself might be a fine place to get air, depending on its air flow.

Thanks I've got another CO2 meter ordered that I can move around the house and I'll check the attic.

 

[rishma]

I ran a CO2 scrubber on an older tank but got tired of replacing media so often... are there any studies to the effectiveness of bringing in outside air if you have to go really long distance? I'd have to send a hose up my wall and over to a soffit in the attic. It's very doable but probably 40 - 50 ft total with a few bends or curves.

I run an airline 35-40 feet for this purpose.

 

[reefmaster70]

I am in the same boat, and have learned to just let it go, as I fought the "Raise my pH" battle for a year. I wanted my pH to sit at 8.1-8.2 and NOTHING I did would allow me to raise it and hold it there. I ran an airline out a window to my skimmer, nothing, I now have a co2 scrubber attached to my skimmer, and was changing the media as soon as it would turn blue (usually a week)..I could get my ph up to maybe 8.0 at that point..otherwise, my tank lives 7.6-7.8 range constantly. I've given up trying to raise it. All inhabitants are great, no issues.

my tank parameters
temp: 78.5
Alk: 8.0
phos: .1
Nitrate: 12ppm
Cal: 460
Mag: 1400ppm

PH: 7.6

 

[mook1178]

So CO2 in the air does not change the pH directly. CO2 in water does. CO2 in air will only tell us which way the CO2 is moving, in or out, compared to the pCO2 in the water. Secondly, at dKH of ~7.5, natural seawater, the pH is 7.9 at 400 uatm pCO2 using CO2sys. I think your calculations are off

 

[HARDY CORALS]

I ran a CO2 scrubber on an older tank but got tired of replacing media so often... are there any studies to the effectiveness of bringing in outside air if you have to go really long distance? I'd have to send a hose up my wall and over to a soffit in the attic. It's very doable but probably 40 - 50 ft total with a few bends or curves.

I would try the long run. Just use a much bigger diameter pipe / hose than needed. I do not think it would add resistance to the pull from the skimmer if it was twice the size needed.
Pex pipe comes to mind 1/2" maybe.

 

[mook1178]

Start of test - Tankwater
Apex was 7.84

End of test -
Apex in aerated cup was 7.72
Apex in tank at end of test was 7.83

So I ended up lowering my PH a little bit.

Do this test outside