Increase KH after every water change?

[Flare]

Hi,

I'm wondering, after every 50% water change weekly, do I need to increase the KH? I have a 50USG tank with CO2 injection. The KH currently is 4dKH. I presume after a 50% water change, the KH will be 2dKH. (I haven tested as I just started adding Baking Soda to increase the KH this week). Do I need to increase the KH immediately after the water change?

[ckll]

When you remove 50% of the water, the remaining 50% in tank still measures 4dKH. If you top it up with tap water, then it will be 2dKH.

If your aim is to maintain kH at 4dkH, then yes, do add the baking soda to get it back to 4dkH.

[chua]

Hi,

It is not really necessary to maintain a KH of 4.
As long as your KH is not below 1.
It is good enough as a buffer.
Hence, you may wan to increase your KH only when it drops below 1.

Thks.

[tawauboy]

to prevent stressing your fishes too much, don't increase hardness by more than 2dkh in a 24hours period.

[Flare]

Hi,

Chua, so it is not necessary to maintain a KH of 4? Well, I've read alot on the net and I get confused sometimes. Some say a KH between 4 and 10, and now not below 1? Anyway, I guess every tank differs in their own chemistry. As long as plants r growing well, fishes health r good, I guess there's not really a need to follow. The info basically serves as a guideline. Thats what I think. Rite?

[tawauboy]

a kh of > 1 ensures that you will not have ph crash.
kh/ph relationship is used to determine your co2 concentration.

if you keep have some critters that have small ph range tolerance, then the kh value becomes important. you decide the ph (from critter requirement) and obtain the corresponding kh.

[PeterGwee]

Do note that some plants take in carbonate as a form of carbon for photosynthesis. Hence the risk is that if you keep the KH too low and the carbon requirement in the form of CO2 is low and not met, you might encounter a pH crash as the carbonate get used up by the plants.

Regards
Peter Gwee