what is elevating my PH?

[venzi]

Hi.  I just tested my 20H tank water for PH and found it to be 8.2.  My tap water is at 7.6.  What can cause the PH to increase by this much?  Water temp is around 76F.  I just have gravel in there (no coral or anything).  I have good flow in the tank (around 100 gph) that's aerating the water at the surface via water turbulence.  I read that highly oxygenated water can raise PH, but it can raise it by this much?

edit: assuming the PH elevation is due to oxygenation, would the PH go down a little if I were to reduce the flow to like 30gph?  How long would I have to wait before measuring the PH (like when would it reach equilibrium)?

Edited August 31, 2022 by venzi

[nabokovfan87]

What kind of gravel? Does any of it have white pebbles or marbling on the rocks?

I don't think oxygenation would raise it that much. Because there's a discrepancy between the tank and the tap I would run an off-gas test.

A.  Take a sample from your tap and test that for everything you can.
B.  Take that same sample and aerate it with an airstone for 24 hours, re-test. (this is what your tank would see when you do a WC)
C.  Compare test B results to your tank parameters.

[SimmonsSnailsNScales]

On 8/31/2022 at 12:42 AM, nabokovfan87 said:

Take that same sample and aerate it with an airstone for 24 hours, re-test. (this is what your tank would see when you do a WC)

I have never heard this before. Fascinating. 

[venzi]

On 8/30/2022 at 10:42 PM, nabokovfan87 said:

What kind of gravel? Does any of it have white pebbles or marbling on the rocks?

It's the natural rock type from walmart 

I'll try to isolate as you suggest and test again.  Thanks @nabokovfan87

[Jenja]

Are you regularly doing WCs? If you aren't regularly taking out water, just topping up evaporation then every time you do that you are adding in kH (depending on how high your tap's kH is you might have raised it significantly). As you know kH buffers the water, so as that increases so would the pH. I'd measure kH, tap* and tank and see if they match or if your tank is higher.

Edited August 31, 2022 by Jenja
Typo

[face]

do you know what your kh and gh are? if its just ph i wouldn't worry about it to much ph is relatively unimportant changing it with out changing kh gh or tds will likely not be noticed by your fish and its really not worth changing the other things unless your having problems or your going for something specific like breeding.

[JettsPapa]

What is the stocking in the tank?  Unless it's something that really needs low pH I wouldn't worry about it too much (assuming it doesn't keep rising).  I have a wide range of fish, shrimp, and snails doing just fine in 8.2 pH water.

[modified lung]

Tap water often come with elevated CO2 which lowers its pH. After sitting in a bucket for a while or being added to you tank, the CO2 off gasses over time which causes your pH to go up (or more accurately, it causes your pH to return to normal). It's aeration or water turbulence/turnover, not oxygenation, that raises pH by off gassing the CO2. 

[venzi]

On 8/31/2022 at 12:48 PM, modified lung said:

(or more accurately, it causes your pH to return to normal).

Wow good to know.  Thank you.  I'm gonna have to run a test now.  I have some tap water sitting in a cup.  How long do I need to wait for the CO2 to off gas?  Give it 24 hours?

[modified lung]

On 8/31/2022 at 1:32 PM, venzi said:

How long do I need to wait for the CO2 to off gas?  Give it 24 hours?

Not 100% sure but I think 24 hours should do it.

[rockfisher]

There are a few ways to lower ph peat in the filter is one. I use pantyhose and stuff the size I want with peat moss and tie them off. You can put it in your tank as well but if you have plecos I would not because the fins and denderals can get stuck in the hose. The second I saw here and use it but scaled it down to a 5 gal bucket.

I usein stead of Muradic acid 
 

there are other over the counter ph lowering products but I have not had any issue with these, but have with some of the store stuff. No matter what don’t change the ph fast. The peat with change it slow but it may not get it to the point you want. If you do the second I would do small water changes so the ph does go down but slower.

[Hobbit]

Lots of great advice here! I did have gravel that raised my pH: it was from one of the big box stores and turned out to be some sort of white stone coated in a black paint. One easy way to tell if it’s your gravel is to get two cups and fill one with water, and the other with half gravel and half water. Let them both sit for a week and then test the pH.

[venzi]

@nabokovfan87  @modified lungWow so this is completely unexpected.  I couldn't wait a full 24hours 🙂I had 3 samples to test.  

1. RO water
2. tap water
3. tap water added to a nano tank (it has no fish, just a mini HOB filter and some gravel).  This was to simulate an air stone (since I don't own one and the mini HOB was what I had).

The water samples were added in the afternoon and I tested the water around midnight so about 8 hours or so.  And here are the results

1. Fresh RO Water 6.6 PH
2. 8 hour RO Water 7.4 PH
3. Fresh tap water 7.6 PH
4. 8 hour tap water 8.2 PH
5. 8 hour tap water in nano tank w/ HOB  8.0 PH
   1. no clue why this PH is lower

So even if I'm misinterpreting the color hues for the API test kit, judging by the pictures anyone can make a relative comparison and it's no question some vials are darker than the others.  I do use a water conditioner (not water softener), but I don't think that's supposed to change the PH.  I can get a sample of water that doesn't go through the water conditioner and test that perhaps.

I was excited that my fresh tap water was 7.6 PH b/c that's the perfect range to grow beneficial bacteria.  Now that I"m facing 8+ PH, I think I need to consider methods to lower water PH (thanks for your post @rockfisher )

picture of fresh RO water I'm guessing around 6.6 PH

 

[nabokovfan87]

On 9/1/2022 at 12:41 AM, venzi said:

The water samples were added in the afternoon and I tested the water around midnight so about 8 hours or so.  And here are the results

1. Fresh RO Water 6.6 PH
2. 8 hour RO Water 7.4 PH
3. Fresh tap water 7.6 PH
4. 8 hour tap water 8.2 PH
5. 8 hour tap water in nano tank w/ HOB  8.0 PH
   1. no clue why this PH is lower

It is pretty relevant to have KH along with these results.

Because of the ones that are in the 7.4-7.6 range and that's low on that high range PH test, I would recommend retesting those for clarity on the low PH test.

[JettsPapa]

On 9/1/2022 at 2:41 AM, venzi said:

. . . Now that I"m facing 8+ PH, I think I need to consider methods to lower water PH (thanks for your post @rockfisher )

Did you see my reply above?

[modified lung]

On 9/1/2022 at 12:41 AM, venzi said:

@nabokovfan87  @modified lungWow so this is completely unexpected.  I couldn't wait a full 24hours 🙂I had 3 samples to test.  

1. RO water
2. tap water
3. tap water added to a nano tank (it has no fish, just a mini HOB filter and some gravel).  This was to simulate an air stone (since I don't own one and the mini HOB was what I had).

The water samples were added in the afternoon and I tested the water around midnight so about 8 hours or so.  And here are the results

1. Fresh RO Water 6.6 PH
2. 8 hour RO Water 7.4 PH
3. Fresh tap water 7.6 PH
4. 8 hour tap water 8.2 PH
5. 8 hour tap water in nano tank w/ HOB  8.0 PH
   1. no clue why this PH is lower

So even if I'm misinterpreting the color hues for the API test kit, judging by the pictures anyone can make a relative comparison and it's no question some vials are darker than the others.  I do use a water conditioner (not water softener), but I don't think that's supposed to change the PH.  I can get a sample of water that doesn't go through the water conditioner and test that perhaps.

I was excited that my fresh tap water was 7.6 PH b/c that's the perfect range to grow beneficial bacteria.  Now that I"m facing 8+ PH, I think I need to consider methods to lower water PH (thanks for your post @rockfisher )

picture of fresh RO water I'm guessing around 6.6 PH

 

Nice, I always like it when people report back. 

Because RO water has no KH, the pH can be all over place depending on conditions. Idk why it went up so much in your case. I've never use RO.

For your tap water, if you test your KH and it's really high, that would confirm there's CO2 in your tap. 8.2 pH usually goes with high KH. There usually isn't enough CO2 in tap water to be a big deal but some cities do weird stuff to their water. 

For the nano tank, I'd guess the pH went down a little because of some metabolic activity happening in the gravel, bacteria or other microorganisms.

Like @JettsPapa said, I wouldn't mess with your pH unless you want fish that really really need low pH.

[Hobbit]

I agree that I wouldn’t worry about the pH in terms of your beneficial bacteria. I’ve been running a tank at a high-ish pH for over a year and it’s never had an issue with BB. As long as they have plenty of surfaces to grow on, you should be fine. It’s more about the fish and plants you want to keep and what they need.

[venzi]

On 9/1/2022 at 12:48 AM, nabokovfan87 said:

, I would recommend retesting those for clarity on the low PH test.

I've tested the fresh tap water w/ low ph test before and it was like solid blue (basically darker blue than the highest color on the low ph scale).

@JettsPapa  oh oops.  Yea, maybe I'll leave it alone.  I'm all about low maintenance and if I can get away with not having to fight against the natural PH of my tap, I would rather not 🙂

Oh general question, I've read that PH naturally goes down in the tank over time.  What are the causes of it and typically from your experiences how fast does it drop (like weeks? months?) and by how much ?

Edited September 1, 2022 by venzi

[JettsPapa]

On 9/1/2022 at 11:43 AM, venzi said:

@JettsPapa  oh oops.  Yea, maybe I'll leave it alone.  I'm all about low maintenance and if I can get away with not having to fight against the natural PH of my tap, I would rather not 🙂

That's a good plan.

On 9/1/2022 at 11:43 AM, venzi said:

Oh general question, I've read that PH naturally goes down in the tank over time.  What are the causes of it and typically from your experiences how fast does it drop (like weeks? months?) and by how much ?

I won't say that isn't correct, but I haven't seen it.  Someone else may have more information.

[modified lung]

On 9/1/2022 at 9:43 AM, venzi said:

Oh general question, I've read that PH naturally goes down in the tank over time.  What are the causes of it and typically from your experiences how fast does it drop (like weeks? months?) and by how much ?

Peat moss and drift wood will lower pH but in my experience it takes a lot and a long time.  Botanicals like dried leaves and alder cones do the same.

Nitrifying bacteria lowers pH over time. How fast depends on how much you feed. They eat 7 ppm of bicarbonate alkalinity (which is how the pH gets lowered) for every 1 ppm of ammonia they convert to nitrate.

For most aquariums you'd have to not do any water changes for months to see a good drop. But if you let them go forever, they'll bring your KH to 0 and pH to around 6.5 sometimes lower.

Some plant substrates will lower pH. My UNS Contrasoil lowers pH relatively fast. Maybe by 1 pH over a month, but I never actually measured how fast so that might be off.

Edited September 1, 2022 by modified lung

[face]

On 9/1/2022 at 12:43 PM, venzi said:

Oh general question, I've read that PH naturally goes down in the tank over time.  What are the causes of it and typically from your experiences how fast does it drop (like weeks? months?) and by how much ?

in hard water ph over lang periods of time will tend to go up because minerals don't evaporate so every time you top off the aquarium minerals get added than water evaporates than more minerals get added and so on and so forth . 

 

in my very soft water my ph go's down because i have almost no kh in my water the right one is tap the middle is after 24 hours the left is after 1 week

 

On 9/1/2022 at 2:06 PM, modified lung said:

Nitrifying bacteria lowers pH over time. How fast depends on how much you feed. They eat 7 ppm of bicarbonate alkalinity (which is how the pH gets lowered) for every 1 ppm of ammonia they convert to nitrate.

just because I'm pedantic its closer to 6 most stuff is in nh3-n aquarium tests are nh3 also some bacteria can us co2 but that's going way down the rabbit hole lol

[modified lung]

On 9/1/2022 at 3:11 PM, face said:

just because I'm pedantic its closer to 6 most stuff is in nh3-n aquarium tests are nh3

True. I have a habit of using the terms interchangeably because I'm lazy.

[Jawjagrrl]

On 9/1/2022 at 12:43 PM, venzi said:

@JettsPapa  oh oops.  Yea, maybe I'll leave it alone.  I'm all about low maintenance and if I can get away with not having to fight against the natural PH of my tap, I would rather not 🙂

I've always planned my fish based on my water, not the reverse. But given how many fish are aquarium/farm bred today in a wide range of water parameters, it's less an issue today than when I started decades ago. If you have any lingering concerns about fish in 8.2 water, just check out Prime Time Aquatics channel. They are keeping tons of stuff at that exact PH.

Quote

Oh general question, I've read that PH naturally goes down in the tank over time.  What are the causes of it and typically from your experiences how fast does it drop (like weeks? months?) and by how much ?

Typically it's going to be the reverse, especially if you top up more than doing water changes. But perhaps what you read refers to heavily planted tanks with lots of wood - organics breaking down will lower Ph. I have two 75s that have been running for a few months, one with CO2 and very heavily planted - the other has no CO2 and just a few. Both have wood and botanicals, but the one with CO2 and many plants is running about 6.8, while the other is around 7.3. Tap is 7.1-7.2.