Gh and Kh levels.

[Tailsjam]

My brother in law has set up a new tank. It's been running about a week now but his Gh and Kh levels are off the chart. Can anyone suggest what they should be and how to bring them down?

 

[phin]

what do you mean by off the chart? If you are using the liquid drop test kits by API there is no chart. The reading is the number of drops it takes to turn the water in the test tube from yellow to blue or green to yellow, depending on what you are testing.

The answer to your question really depends on the type of fish you are keeping and if you are trying to breed them. I have bred african cichlids if Gh as high as 32 dGh, but have adjusted my mbuna tank down to about 22 dGh. Kh is your carbonate hardness and a measure of the alkalinity buffering capacity. A higher Kh will guard against pH swings, but makes keeping tanks at a lower pH hard. The kH will have to be altered before the pH can be lowered.

Anyway, what kind of fish are you keeping and what are the exact readings?

 

[Tailsjam]

I believe he is using strips to test. He says they are the highest they can go. I will find out more and report back.

 

[jlk]

+1 @Phin

Strips measurements for gh & kh simply are not accurate. Unless your BIL wants keep a sensitive or difficult species of fish, I wont worry about the gh & kh. The only way these can really be reduced is to cut the tap water with RO or switch completely to RO (reconstituted).