Ph and Alkalinity

[GillMeister]

I have alkalinity running about 9.5 and calcium is approximately 400-450. My Ph, however, is stubbornly low at about 7.9. Is there something I'm not doing right?

 

[proxy001]

First, check calibration of probes. Second 7.9 in the morning is within normal limits.
If all calibrated and 7.9 at the end of the day, you could
-Run a CO2 scrubbier
-Open the windows

Overall, the opinion is that Ph doesn't matter if within range which you are. I know BRS did a myth muster on that and if I recall demonstrated that higher Ph was associated with better growth.

 

[chipmunkofdoom2]

Calcium has no relationship to pH. Alkalinity does to an extent, but alkalinity is only a small part of pH. For the most part, pH is controlled by CO2.

This article Randy wrote sums it up well.

 

[anth]

I had this issue. I was dosing 2ml a day of triton core 7. My tank ph was 7.8-7.9
I installed a co2 scrubber and my ph went up to 8.5 and now dose 11.5ml of core 7.
I am now adjusting the scrubber to give me a ph of 8.3-8.4.

 

[HuduVudu]

Calcium has no relationship to pH. Alkalinity does to an extent, but alkalinity is only a small part of pH. For the most part, pH is controlled by CO2.

This article Randy wrote sums it up well.

CO2 <-> H2CO3 <-> HCO3 <-> CO3

Alkalinity is a HUGE part of PH.

 

[GillMeister]

my understanding is alkalinity helps keep those ph swings under control as well. I've dosed soda ash to stabilize and it seems like it helps a little bit. Still would like to get the ph where I don't have to worry about it so much. My probe is calibrated, by the way, and verified with two other test methods.

 

[Randy Holmes-Farley Verified Community Expert]

my understanding is alkalinity helps keep those ph swings under control as well. I've dosed soda ash to stabilize and it seems like it helps a little bit. Still would like to get the ph where I don't have to worry about it so much. My probe is calibrated, by the way, and verified with two other test methods.

Yes, higher alk tends to reduce the pH swing, and to raise both the lower and higher end of the daily swing.

Both alk and CO2 contribute "equally" to the pH (mathematically), but the range of alk experienced by reefers is about a factor of 2, while the CO2 level easily ranges by more than a factor of 10 between reef tanks and between times of day, and hence the impression that it has a bigger effect (which it does in that sense).

 

[GillMeister]

Thank you Randy. My next step will be to tell the Wife to stop breathing so much. Problem(s) solved.

 

[Dr. Jim]

I recently plumbed a PVC pipe from the window to the skimmer. The pH went from about 7.80-8.10 to 8.17-8.35. I ordered a CO2 scrubber at the same time but found that I don't really need it!

 

[GillMeister]

I recently plumbed a PVC pipe from the window to the skimmer. The pH went from about 7.80-8.10 to 8.17-8.35. I ordered a CO2 scrubber at the same time but found that I don't really need it!

I live in Minnesota. My skimmer would become a nasty greenish brown icicle in the winter.

 

[beaslbob]

IMHO adding macro algae in a refugium will lower co2 and raise Ph

 

[HuduVudu]

IMHO adding macro algae in a refugium will lower co2 and raise Ph

If the CO2 in the house is too high then this won't work, unless you work to seal the house from the tank.

 

[proxy001]

Trying to "cheat" will alk doesn't work.
I had my Alk at 10 and my max ph a 8.1

Now, a miracle has happened, first time I ever go above 8.3

 

[beaslbob]

If the CO2 in the house is too high then this won't work, unless you work to seal the house from the tank.

Not in my experience. Even my fw planted tanks with peat moss in the substrate and no circulation have Ph values over 8. Macro algae will raise Ph because it consumes co2. With no dosing co2 like in a calcium reactor, the tank becomes a net source of oxygen and co2 sink to the surrounding environment. Such that the lowest macro Ph is much higher than the highest non algae tank.

 

[HuduVudu]

Not in my experience. Even my fw planted tanks with peat moss in the substrate and no circulation have Ph values over 8. Macro algae will raise Ph because it consumes co2. With no dosing co2 like in a calcium reactor, the tank becomes a net source of oxygen and co2 sink to the surrounding environment. Such that the lowest macro Ph is much higher than the highest non algae tank.

The only difference is that salt water tanks (should) have more surface agitation and gas exchange, but if they don't this is a good solution. Also there are more plants in a fresh water planted per volume.

Ultimately though I don't disagree that this is possible.