Dropping KH?

[Ramirez]

Can anyone explain why my KH drops in my 55 gallon planted aquarium. The KH out of the tap is 3, but the KH of my tank is 2. Even after weekly water changes, the KH is 2.

Are the plants using up the some of the bicarb?

 

[djlen]

Do you have Valisneria in the tank?
Some plants use kH more than others. Val. is one of them.
It would probably be a good idea to raise your kH anyway, especially if you are now or ever in the future decide to inject CO2.

Len

 

[pl*co]

Do you have driftwood in the tank? That'll drop it.

 

[RTR]

It is most likely just normal nitrification if the tank is heavily stocked and water partials are not large enough often enough. What is the nitrate level in the tank?

 

[Ramirez]

Yes there are Vals in the tank. Only a small grove of sprial vals.

Yes there is driftwood.

I'm currently injecting DIY CO2, but it is not enough for a 55. I'm thinking of going to pressurized, but would like to figure out why my KH drops, first.

The nitrates are 5-10 ppm. I dose iron, nitrate, potassium. If anything the nitrates are on the low side because I have had to recently increase them to keep away BGA

 

[mdfwhite]

kh also drops with water changes ,kh does not affect your fish directly,its to stablize your ph,if your ph isnt fluctuating badly i wouldnt be to concerned.Mines on 2dkh also and my fish are ok.
If it worries you try a kh up product,and only if you know what your doing(limestone or calcium carbonate)they increase gh / kh which inturn increases ph.

 

[happychem]

kh also drops with water changes

I'm afraid I don't follow you with this statement. His tap is 3, if there were no change, the tank should also be 3.

If your CO2 is low, decalcification is a definite possibility.

Acidification from the natural nitrification process is another possibility.

I doubt that the driftwood is to blame unless it's brand new. If you were seeing that magnitude of change, one would also expect tannic water.

 

[RTR]

KH directly affects the fish more significantly than does the pH, as KH is a non-trivial part of the osmolarity of the water.