How can I stabilize pH?

[Dade]

The pH in my 60 gallon tank keeps dropping. It will stay at about 7.2-7.4 for a while and then, when I check again a few days later, it will have dropped to about 6.0!

I add baking soda to get the pH back up and it works for a week or so and then the same thing happens again.

 

Anyone seen this? And how can I stabilize my pH?

[anewbie]

First do not add backing soda until you figure out why the ph is dropping. Having it drop and then suddenly raising it is worse than just leaving it alone after the drop if the bottom is 6 (which is not bad for the fishes pictured). More details would need to be provided - a few things that might help include:

age of the tank

type of substrate

kh

any additives being added on a regular basis

is this a hi-tech tank (are you adding co2) 

 

[Frank]

To add to what @anewbie said, another question is: Is this a new issue with an established tank?

Many people use crushed coral. 

Link:

 

[Dade]

Hi, all.

The tank is not quite 3 months old. I regularly add minerals and fertilizer (including root tabs). I also add calcium. The tank is heavily planted. 

I've got wood, almond leaves, and CO2, all of which I know drop pH. 

The substrate is fertilized gravel. 

Any other data I can provide that will explain better?

[anewbie]

Both CO2 and almond leaves will drop the ph - the thing is that when the CO2 goes off the ph will rise. You should measure or have your kh measured. If the kh is low enough the tank can crash. If your base ph is 7.2 and you add enough co2 daily to drop it to 6.4 (which would be normal) then the almond leaves might have contributed to the additional drop and there really isn't an issue.

-

The calcium you add should increase the kh (same as adding coral mentioned by @Frank); so it is unlikely anything odd is happening and all is normal.

-

One thing you should do is measure the tank ph BEFORE the co2 turns on in the morning to get a baseline. You don't really want to measure it when it turns off in the evening because you don't know how long it will take for the co2 to gas off and while the co2 is gassing off the ph will rise.

Edited April 4, 2021 by anewbie

[DaveSamsell]

4 minutes ago, Dade said:

Hi, all.

The tank is not quite 3 months old. I regularly add minerals and fertilizer (including root tabs). I also add calcium. The tank is heavily planted. 

I've got wood, almond leaves, and CO2, all of which I know drop pH. 

The substrate is fertilized gravel. 

Any other data I can provide that will explain better?

Just curious, how often do you change water and what percentage?

[Dade]

I change water every 14 days, about 25%. My nitrates are almost nil, even after 14 days. I suppose it's because my plants are absorbing them. (Tank is heavily planted).