pH Calculator

[stephenhall1987]

Is there a calculator or a formula for raising pH? I looked at The Reef Chemistry Calculator, Hamzasreef, BRS, etc.

Example: 100 gallons of saltwater, raise pH 1.0 using Kalk, or Sodium Carbonate, or Sodium Hydroxide, etc.

 

[Randy Holmes-Farley Verified Community Expert]

No, there is no calculator for pH.

When first added, carbonate boosts pH by about 0.35 pH units for each 1.4 dKH of alk added. The boost is larger at lower starting pH and lower alkalinity.

When first added, hydroxide boosts pH by about 0.65 pH units for each 1.4 dKH of alk added. The boost is larger at lower starting pH and lower alkalinity.

In both cases, pH will typically start to decline slowly after adding it as the tank pulls in more CO2 from the air.

 

[stephenhall1987]

Ok thank you!

Right now I'm trying to raise the pH of my newly mixed saltwater, but I thought the formulas would be handy in general. After mixing reef crystals with my DI water (even letting mix for days), the pH is often in the 6.6 area. My tank stabilizes at 8.1, but I'd like to get the new water higher before doing water changes.

 

[Randy Holmes-Farley Verified Community Expert]

Ok thank you!

Right now I'm trying to raise the pH of my newly mixed saltwater, but I thought the formulas would be handy in general. After mixing reef crystals with my DI water (even letting mix for days), the pH is often in the 6.6 area. My tank stabilizes at 8.1, but I'd like to get the new water higher before doing water changes.

Something is amiss. The pH of newly mixed salt water cannot be pH 6.6. Do you mean 7.6?

I would not add anything to boost pH in new salt water. it will just end with excessive alk.

 

[stephenhall1987]

New Saltwater:
salinity 1.026 Milwaukee digital refractometer
I dosed enough Sodium Carbonate to raise the dKH 1 point (to raise pH).
dKH now 10 api
pH now 7.1 api
pH now 7.01 Hanna pen
pH of freshly made DI (Culligan filter) water 5.14 Hanna pen

 

[Randy Holmes-Farley Verified Community Expert]

The Hanna pen needs calibration. Those seawater values are far off.

 

[stephenhall1987]

Aquarium water:
Salinity 1.026
pH 8.2 api
pH 8.20 Hanna pen

It seems to work on the aquarium. The new water seems to always be a low pH. I have wondered if Culligan's DI resin might be releasing a chemical that is lowering the pH, maybe what ever they use to recharge the resin.

 

[gbroadbridge]

Aquarium water:
Salinity 1.026
pH 8.2 api
pH 8.20 Hanna pen

It seems to work on the aquarium. The new water seems to always be a low pH. I have wondered if Culligan's DI resin might be releasing a chemical that is lowering the pH, maybe what ever they use to recharge the resin.

Try another pH probe dual point calibrated with fresh pH 7 and ph 10 buffer solutions.

 

[Randy Holmes-Farley Verified Community Expert]

Aquarium water:
Salinity 1.026
pH 8.2 api
pH 8.20 Hanna pen

It seems to work on the aquarium. The new water seems to always be a low pH. I have wondered if Culligan's DI resin might be releasing a chemical that is lowering the pH, maybe what ever they use to recharge the resin.

I guarantee the pH is inaccurate in the new salt water if the alkalinity is actually 10 dKH (or anything above 7 dKH) and you aerated it at all.

The only alternative is for the CO2 level that the new salt water is aerated with is so high in CO2 that it is dangerous for you to be in the same room. It would need to be above 4,000 ppm.