How do I lower my ph?

[PegasisR]

My ph is consistently running at 9.1 and trust me it isn't a test error because the probe measuring it has been replaced and calibrated. How can I lower my ph? Thank you!

 

[AydenLincoln]

What salt are you using? And is the tank in a place where the windows or doors are always open? Are you dosing anything?

 

[gbru316]

Stop adding so much kalk?

If it's legitimately 9.1 (I have my doubts) - you need to be dosing significant volumes of something to raise it that high assuming you're starting out with RO/DI and salt mix. It doesn't climb that high on it's own.

Have you verified with a test kit?

 

[Reef.]

Not so fast, are you adding a product that has the affect of raising ph? Stopping or reducing that product may be the better solution than trying to lower your ph another way, whilst still adding the ph boosting product…and yes your reading could be wrong, even with a change of probe.

I have just tested my alk with the Hanna check, got a slightly high reading that I wasn’t expecting, so opened a new reagent bottle, got exactly the same reading! Did I attempt to lower my alk? No I tested it again with Salifert and aquaforest, both test kits gave the same reading of 1dkh lower than the Hanna, lesson is do not take any action until you are 100% sure of your test results.
Giving you the benefit of the doubt I am guessing you are not adding any ph boosting products, as you would then not be so sure your test results are correct, therefore leading me to think your reading of 9.1ph is indeed wrong.

 

[PegasisR]

What salt are you using? And is the tank in a place where the windows or doors are always open? Are you dosing anything?

Salt is Reef crystals and 2 part is ESV
Alk is running at 7.7

 

[Garf]

Salt is Reef crystals and 2 part is ESV
Alk is running at 7.7

Increasing aeration should help normalise it. Do you have a skimmer running? Are you growing a kelp forest, or loads of other algae’s?

 

[PegasisR]

Not so fast, are you adding a product that has the affect of raising ph? Stopping or reducing that product may be the better solution than trying to lower your ph another way, whilst still adding the ph boosting product…and yes your reading could be wrong, even with a change of probe.

I have just tested my alk with the Hanna check, got a slightly high reading that I wasn’t expecting, so opened a new reagent bottle, got exactly the same reading! Did I attempt to lower my alk? No I tested it again with Salifert and aquaforest, both test kits gave the same reading of 1dkh lower than the Hanna, lesson is do not take any action until you are 100% sure of your test results.
Giving you the benefit of the doubt I am guessing you are not adding any ph boosting products, as you would then not be so sure your test results are correct, therefore leading me to think your reading of 9.1ph is indeed wrong.

I totally understand where youre coming from and ill cross check with another kit but it doesnt make sense when a brand new apex probe and calibration are reading the same as the replaced probe

 

[PegasisR]

Increasing aeration should help normalise it. Do you have a skimmer running? Are you growing a kelp forest, or loads of other algae’s?

Algae free and running a skimmer 24/7

 

[Garf]

Algae free and running a skimmer 24/7

Sounds like you need to do the aeration test normally advised for folks with low pH, but this test would see if you can drive CO2 into the water to reduce the pH reading.

 

[PegasisR]

Stop adding so much kalk?

If it's legitimately 9.1 (I have my doubts) - you need to be dosing significant volumes of something to raise it that high assuming you're starting out with RO/DI and salt mix. It doesn't climb that high on it's own.

Have you verified with a test kit?

No kalk or ph boosting additives are in use

 

[Reef.]

I totally understand where youre coming from and ill cross check with another kit but it doesnt make sense when a brand new apex probe and calibration are reading the same as the replaced probe

There was an exact same thread to this, the op protested it wasn’t the probe, turned out it was the probe.

 

[gbru316]

No kalk or ph boosting additives are in use

Then it's your probe -- or calibration thereof -- that's causing the elevated pH reading. 100%.

 

[Randy Holmes-Farley Verified Community Expert]

I totally understand where youre coming from and ill cross check with another kit but it doesnt make sense when a brand new apex probe and calibration are reading the same as the replaced probe

That makes a lot more sense than pH 9.1, which is 100% guaranteed error. Even if you massively overdosed super high pH alk supplements, when the pH hits high levels like that (as I have several times) precipitation of calcium carbonate and magnesium hydroxide turns the tank white like milk and also lowers pH again.

 

[Dburr1014]

I totally understand where youre coming from and ill cross check with another kit but it doesnt make sense when a brand new apex probe and calibration are reading the same as the replaced probe

How did you calibrate it? Manual or the automatic?
What solutions did you use? 7 and 10 or 4 and 7?did you select the right ones?

 

[fryman]

That makes a lot more sense than pH 9.1, which is 100% guaranteed error. Even if you massively overdosed super high pH alk supplements, when the pH hits high levels like that (as I have several times) precipitation of calcium carbonate and magnesium hydroxide turns the tank white like milk and also lowers pH again.

I've seen pH reach 9 in a mature phyto culture, but that's probably from the phyto stripping out CO2, right?

OP, I don't suppose your tank water is a very dark green color, is it? Assuming not and so as others have said it must be test error.

 

[Crustaceon]

I'm assuming this is an errant ph probe reading and it is possible to get such a reading even after calibration with a bad probe. As the notorious RHF (in a positive way) mentioned, if your ph is actually that high, you're going to have noticeable precipitation issues. It'll be so bad your display panels will look "chalky" on the wet sides.

 

[Randy Holmes-Farley Verified Community Expert]

I've seen pH reach 9 in a mature phyto culture, but that's probably from the phyto stripping out CO2, right?

OP, I don't suppose your tank water is a very dark green color, is it? Assuming not and so as others have said it must be test error.

Such a culture may not have seed crystals of existing calcium carbonate surfaces, but magnesium hydroxide may well precipitate from many tanks at that pH.

 

[Uncle99]

Never had much luck long term with any PH probe.
They work, then drift.
No long follow PH, I maximized what I could, and never measured it again.
9.1 is that even possible?

 

[arking_mark]

Never had much luck long term with any PH probe.
They work, then drift.
No long follow PH, I maximized what I could, and never measured it again.
9.1 is that even possible?

Possible with 20ppm CO2 (outdoor air is 400ppm). How you strip out that much CO2 is the challenge...

 

[gbru316]

Possible with 20ppm CO2 (outdoor air is 400ppm). How you strip out that much CO2 is the challenge...

What, you don't run pure O2 in your skimmer?

If you ignite the skimmer exhaust, you can also heat your tank with it.