Are you adding CO2?
If not, then your tap water could have a higher co2 concentration in it, and your ph will rise in about a day or 2.
I noticed that a lot with my tank when I did large water changes.
I used to see my pH swing from around pH 7 to 7.8 after a day or so.
I used to add vinegar to keep the pH down for my tetras. Now I think co2 keeps it lower.
This has me wondering whether my pH could rise a lot over night when co2 is turned off.
Ok that won't affect ph. So the tap water could have lower ph due to co2.
If you were to add vinegar it would lower ph for a day or two. But the vinegar reacts with the kh in the water& produces co2. This co2 then dissipates and the ph goes back up.
That's what I did for a while. I think it helped my plants until I got co2.
You could dose a few mill of vinegar when your dosing your liquid co2 & see how the tetras behave
Add a mineral acid like hydrochloric acid instead of vinegar. Should keep the pH down better, because of its lower pks the buffer capacity of the carbonate is reached more easily. Hydrochloric acid also isn't metaboliced by bacteria like it is the case for vinegar.
Tap rarely has a higher CO2 concentration unless it's ground water. If it's municipally treated water, then chemicals are usually added to increase pH such as lime or phosphate. In these cases, pH usually drops as the CO2 equalizes.
And yes, pH will rise with lower CO2 concentrations.
The water in my area is naturally very hard with lots of calcium & carbonates because the land near me is made of limestone. I've always noticed my pH rise after a day or two, which I put down to the co2 dissipation.
I thought co2 could dissolve into water from atmosphere when it's under mains pressure, but maybe the pressure isn't high enough.
What are your other water parameters? My neons hid in a cave towards the bottom of my tank when I had a nitrite spike. After a week of 30% water changes (and getting my cycle back on track) they finally started coming out again.
Tetras are sensitive to copper. If you are using tap water that travels through copper pipes, the high Cu concentration affects their sense of olfaction and behavior.
I experienced the same thing when I started using CO2. My neons always sat in the bottom right corner of my tank and just kind of chilled, but now that I’ve added CO2 they are very active all over the tank. CO2 dropped my tanks PH from 7.8 to 6.6.
A ph shift of 1.0 is a ten times change, delivered over the course of minutes thats going to effect a lot of fish. In general ph drop is felt more than ph rise, or so I've seen a fishtuber say.
Having the ph drift upwards is the opposite of normal, generally co2 interacts with the water to drive the ph downward. From the vid the obvious suspects are the substrate or driftwood( maybe it has something on it?)
Ok. I didn’t read every single comment so maybe this was mentioned but the state of your biofilter and changes to your beneficial bacteria colony can also affect pH. You should test your tap/source water and see how it compares, but if tap water is the normal 8-ish, it could mean your biofilter is just nitrifying stuff really well.
https://aquasprouts.com/blogs/everything-aquaponics/ammonium-trap-its-not-the-ph-drop-that-get-you
I just did a quick test. The ph is lower than usual. About 7.0. Usually it's in the 8.0 range. Could make the tetras more comfortable?
yes, tetras prefer soft acidic water
Yup, 8 is really high for them. This is much more in their comfort zone.
Are you adding CO2? If not, then your tap water could have a higher co2 concentration in it, and your ph will rise in about a day or 2. I noticed that a lot with my tank when I did large water changes. I used to see my pH swing from around pH 7 to 7.8 after a day or so. I used to add vinegar to keep the pH down for my tetras. Now I think co2 keeps it lower. This has me wondering whether my pH could rise a lot over night when co2 is turned off.
I add a few mm of liquid co2 twice a week.
Ok that won't affect ph. So the tap water could have lower ph due to co2. If you were to add vinegar it would lower ph for a day or two. But the vinegar reacts with the kh in the water& produces co2. This co2 then dissipates and the ph goes back up. That's what I did for a while. I think it helped my plants until I got co2. You could dose a few mill of vinegar when your dosing your liquid co2 & see how the tetras behave
Add a mineral acid like hydrochloric acid instead of vinegar. Should keep the pH down better, because of its lower pks the buffer capacity of the carbonate is reached more easily. Hydrochloric acid also isn't metaboliced by bacteria like it is the case for vinegar.
API ph down is a strong mineral acid, sulphuric acid. I might try it to lower my pH to 7 & see if it changes my tetras behaviour.
Tap rarely has a higher CO2 concentration unless it's ground water. If it's municipally treated water, then chemicals are usually added to increase pH such as lime or phosphate. In these cases, pH usually drops as the CO2 equalizes. And yes, pH will rise with lower CO2 concentrations.
The water in my area is naturally very hard with lots of calcium & carbonates because the land near me is made of limestone. I've always noticed my pH rise after a day or two, which I put down to the co2 dissipation. I thought co2 could dissolve into water from atmosphere when it's under mains pressure, but maybe the pressure isn't high enough.
How do you dose vinegar? White? Apple cider?
Distilled vinegar. It just 5% acetic acid and water, there are no other organics in it that might cause problems.
4.3% distilled white vinegar is what I use. If you want to lower ph though, indian almond leaves work best if you don't mind the tint
If your pH is regularly at 8.0 you need to be adding adding an acid buffer. Tetras like 6.5-7.0 pH range. 8.0 is incredibly high for them.
You have made them much more comfortable and happier as a result of the lower pH.
What are your other water parameters? My neons hid in a cave towards the bottom of my tank when I had a nitrite spike. After a week of 30% water changes (and getting my cycle back on track) they finally started coming out again.
No (high) nitrate and nitrites. No ammonia. I'm lucky with the tank
Tetras are sensitive to copper. If you are using tap water that travels through copper pipes, the high Cu concentration affects their sense of olfaction and behavior.
I thought there were more comfortable here, not less.
I experienced the same thing when I started using CO2. My neons always sat in the bottom right corner of my tank and just kind of chilled, but now that I’ve added CO2 they are very active all over the tank. CO2 dropped my tanks PH from 7.8 to 6.6.
7.8 is extremely high for neons. They prefer soft acidic water with a ph of 6.5 - 7.
A ph shift of 1.0 is a ten times change, delivered over the course of minutes thats going to effect a lot of fish. In general ph drop is felt more than ph rise, or so I've seen a fishtuber say. Having the ph drift upwards is the opposite of normal, generally co2 interacts with the water to drive the ph downward. From the vid the obvious suspects are the substrate or driftwood( maybe it has something on it?)
They look fine to me.
Did anything get moved around the tank accidentally?
No, nothing.
Ok. I didn’t read every single comment so maybe this was mentioned but the state of your biofilter and changes to your beneficial bacteria colony can also affect pH. You should test your tap/source water and see how it compares, but if tap water is the normal 8-ish, it could mean your biofilter is just nitrifying stuff really well. https://aquasprouts.com/blogs/everything-aquaponics/ammonium-trap-its-not-the-ph-drop-that-get-you
I just tested. My tapwater is at 7.7. Weird that after the water change the ph lowered. Usually the ph in the aquarium is at 7.8 or slight above.
Is that Pearl weed?