Maintaining KH using shells or types of rock...possible??

[Finley]

Hi

I am wondering if there's a better way to maintain my KH without adding it artificially all the time... Situation is:

- The optimum KH for my water/tank is only 3, because more than that and the pH quickly goes up too high and CO2 is compromised. (KH3 gives me a pH of about 7 and respectable CO2.)

- My tank has a huge piece of bog wood in it which leaches... It's a beautiful feature and the catfish love it, so it's staying.

- The tank is well planted, which I presume uses up KH too.

The net result is that the KH drops quickly, and every few days I have to top it up artificially. Is there a type of shell or rock that would keep the KH topped up naturally, but slowly?? In the distant past I found that shells dissolved too quickly and increased the pH too much, but I am willing to try again if I can find something with a mild supporting effect on KH...

Thanks,

Finley

 

[Star_Rider]

so what is the kH of your tank..sometimes you have a stable kH and see a drop in pH due to tannins and or CO2 but the kH remains stable(3-4 dh)

many times this drop in kh is a result of acid in the tank and not a low kH.. remove the source of the acid and the tank pH goes up.
ie co2 created carbonic acid which lowers pH(kh remains constant) turn off the CO2 the pH rises.

other than that you can place crushed coral in a filter bag and place it in the filter..the down side is it may raise the kH and you may wind up with an increased pH. past the desired level.

 

[Finley]

so what is the kH of your tank..sometimes you have a stable kH and see a drop in pH due to tannins and or CO2 but the kH remains stable(3-4 dh)

Thanks SR. The kH and pH drop in unison. e.g. After a few days 'kH3 and pH7' becomes 'kH2 and pH6.6'. I don't add CO2 artificially.

I could add a piece of coral, not in the filter where it will dissolve like crazy, but just in a corner of the tank... Just want to be careful about the wisdom of that, because coral generally doesn't belong in FW.

What gives natural FW systems - rivers etc - their kH?

Finley

 

[Coler]

crushed coral as substrate or in the filter will help to buffer Ph & Kh, so will certain rocks (limestone, tufa...more). This is the kind of stuff people generally use in rift lake cichlid tanks which want to have high numbers.