Skimmer out window, surface boiling, why wont my ph rise?

[skidmarkstevie]

Ive stumbled upon what will certainly be a learning moment for me. My PH is LOCKED at 7.9. Day and night. So much so that if I take a cup of tank water and aerate it for 3 hours outside it is still 7.9. My tropic marin pro reef bucket mixes up at 8.2ph or 8.3 ph just fine inside the house. Is this just from overfeeding and DOC? For what its worth I havent done a water change in about 3 weeks.


1.026
Ph 7.9
Alk 8.5
No3 5.5
Po4 .05

Temp 80

What could cause this ph if my alkalinity is great and my aeration is in abundance with fresh air? Again new water mixes right up, and will stay there with slight mixing. But after removed from the tank I cannot aerate it past 7.9. Id be tickled pink to have an understanding of what is going on here and get back to 8.2-8.3 ph without adding another piece of gear.

 

[Seregus]

What are you using to check ph?
Taking skimmer air intake to outside vs inside made any difference on ph?
Have you tried CO2 scrubber?

Why I’m asking is because my Hanna pH always shows 7.7-7.9 and no any increase after CO2 scrubber installed, while GHL probe shows .2 increase and shows 8.4 pH now…

 

[skidmarkstevie]

What are you using to check ph?
Taking skimmer air intake to outside vs inside made any difference on ph?
Have you tried CO2 scrubber?

Why I’m asking is because my Hanna pH always shows 7.7-7.9 and no any increase after CO2 scrubber installed, while GHL probe shows .2 increase and shows 8.4 pH now…

Im using a brand new bluelab ph probe calibrated with 7 and 10. It responds quickly between the 7.9 tank and 8.2 fresh mix. It also reads a bottle of 9.0 i have here quite well. works great in all my references.

 

[Goofball310]

What size is your tank and how many fish do you have?

 

[skidmarkstevie]

What size is your tank and how many fish do you have?

Total water volume is between 35 and 40 gallons. Ive got 5 fish all about 2-3". I also have very active liverock and other critters.

The problem I have with the respiration theory is that those fish and rock aren't in the cup during the outside air test.

 

[BryanM]

When I see testing results that are "stuck" I almost always think there's a testing error.

This is a good read:

https://www.reef2reef.com/ams/understanding-ph-in-reef-tanks-part-one.1133/

 

[skidmarkstevie]

I wish i

When I see testing results that are "stuck" I almost always think there's a testing error.

This is a good read:

https://www.reef2reef.com/ams/understanding-ph-in-reef-tanks-part-one.1133/

I think the same thing but I must be missing something? Im a water proffessional by trade and quite familiar with testing. These two statements are true.

Used tank water stays at 7.9ph when aerated. Alk is 8.5

Fresh mixed saltwater aerates to ph 8.3 with alk 8 in identical environment.

So now what?

 

[KrisReef]

I don’t know, but you have demonstrated that the pH of the tank has lowered from exposure to the tank conditions and that fresh mixed water has a higher pH.

The lowering of the tank water is not from CO2, or else the pH would increase with aeration.

Something is in the tank, consuming alkalinity.

 

[Fish Fan]

I agree with Bryan that your pH cannot be "locked", it has to fluctuate especially over a 24 hour period. This is almost certainly a testing error. Many R2R members have Apex controllers (including Bryan) that graph pH over time, it's always fluctuating, never just a solid line on a graph.

I think organic material in your tank is potentially working towards lowering your tank's pH vs. the freshly mixed saltwater without any organics.

Most all reef tanks run at a chronically low pH of about 7.9 and do just fine. I know many, many reefers here on R2R that do not bother testing pH.

My opinion is that you should not bother chasing "perfect" pH unless you're growing corals professionally or competitively.

I hope this helps and good luck!

 

[BryanM]

I wish i


I think the same thing but I must be missing something? Im a water proffessional by trade and quite familiar with testing. These two statements are true.

Used tank water stays at 7.9ph when aerated. Alk is 8.5

Fresh mixed saltwater aerates to ph 8.3 with alk 8 in identical environment.

So now what?

Quite honestly I'm not sure.

I'd probably try and verify with a Hanna test kit for PH.

Since the probe is reacting well in test solutions I feel it is unlikely to be any sort of electrical interference.

Hopefully someone with more knowledge responds.

 

[JonasRoman]

I think its a measure error. If you take a marine water with reasonable normal alkalinity and let it get CO2 equlibrium with outside air, you should get pH 8.2. Only reason I can imagine if this is not measure error is that you have so much acid in water of other kind so alkalinity is depleted. Then CO2 equlibrium with outside air will give lower pH. So measure the alkalinity prior to the test. If its normal, and outside aeration doesnt rise pH=measure error. If alkalinity is low, then thats the reason.

Jonas

 

[BryanM]

My PH over the last several days:

 

[zenom73]

I have an Apex PH probe and use Tropic Marin Pro Reef. My pH probe is almost always in the 7.9 range, sometimes in the 8.0x range. It fluctuates from like 7.96 to 8.05 between night and day. Not sure if that helps, but I can rarely get my Tropic Marin Pro Reef to give me any 8.x pH without major co2 exchange and sometimes dosing soda ash.

Also isn't your temp a tad high? Won't that impact your pH as well?

 

[mook1178]

This is what I would do:
Test the alkalinity and pH of the tank. Immediately take a cup of water and place it outside.
Test the alkalinity and pH of the cup after ~5 hours.

Alkalinity should not change, but if pH stays steady, then your alkalinity has to be decreasing. No other way for the pH to stay the same. If alkalinity is decreasing in the cup of water, then you have some sort of organic acid being released by the consumption of DOC.

If alkalinity stays the same and pH stays the same, it is a testing error. I would guess in your alkalinity since it sounds like your pH respond appropriately. Maybe bad reagents.

 

[skidmarkstevie]

As a water proffesional Im pretty familiar with the relationship of temp ph and alk. Maybe my next step would be to check alk after the aeration test of tank water with no critters?

Perhaps that will give me an idea if there's an abundance of acid from organics?

 

[skidmarkstevie]

This is what I would do:
Test the alkalinity and pH of the tank. Immediately take a cup of water and place it outside.
Test the alkalinity and pH of the cup after ~5 hours.

Alkalinity should not change, but if pH stays steady, then your alkalinity has to be decreasing. No other way for the pH to stay the same. If alkalinity is decreasing in the cup of water, then you have some sort of organic acid being released by the consumption of DOC.

If alkalinity stays the same and pH stays the same, it is a testing error. I would guess in your alkalinity since it sounds like your pH respond appropriately. Maybe bad reagents.

Something like this seems to be the case. Will follow up when I have time to repeat the test.

 

[Privateye]

It sounds like you already know the relationship between temp, pH, alkalinity, and CO2, which is awesome!

What sort of alkalinity test do you use? Does it measure carbonate hardness or total alkalinity? Your phosphate is pretty low so I don't think it's doing much buffering (but it will buffer to a very low pH by our standards).

Personally I wouldn't worry too much about 7.9 if the livestock is happy. I also wouldn't worry about a dKH of 9-10 if the same is true, so you could boost it a little if you like. I tend to run a little higher alkalinity (when I'm on top of it) to grant more pH stability. Mostly in systems that have a high alkalinity demand.

 

[Randy Holmes-Farley Verified Community Expert]

I wish i


I think the same thing but I must be missing something? Im a water proffessional by trade and quite familiar with testing. These two statements are true.

Used tank water stays at 7.9ph when aerated. Alk is 8.5

Fresh mixed saltwater aerates to ph 8.3 with alk 8 in identical environment.

So now what?

Then either the tank water alk is wrong, aeration is incomplete, or the pH measurement is miscalibrated. Alkalinity, CO2 levels, and pH are mathematically related, and knowing two gives the third (although the calculation is not trivial unless using a calculator)..

How long did you aerate? and how much for how long?

 

[KrisReef]

Then either the tank water alk is wrong, aeration is incomplete, or the pH measurement is miscalibrated. Alkalinity, CO2 levels, and pH are mathematically related, and knowing two gives the third (although the calculation is not trivial unless using a calculator)..

How long did you aerate? and how much for how long?

Fresh mixed sea water, if the alkalinity perciptates out in the tank as the sea water ages, could this account for the lowered pH results?

 

[Randy Holmes-Farley Verified Community Expert]

Fresh mixed sea water, if the alkalinity perciptates out in the tank as the sea water ages, could this account for the lowered pH results?

Yes, precipitation of calcium carbonate lowers pH (and alk). :)