So I just tested my kh via drops and got. Kh reading of 16.. I was going to use vinegar but I found thats a bandaid.. I am extreamly familier with muriatic acid, but is that actually even safe for the tank? I just lost two clownfish and want to make sure it is right before adding more..
Frank the Fish guy
No you don't want to add it to the tank directly.
The way to reduce KH in water for fish is to put the water in a big barrel. I use 50 gallon drums.
You put in concentrated HCL (muriatic acid) at the rate of 1 teaspoon per 25 gallons. Aerate the water for 24 hours, and then retest the KH. This will permanently lower the KH and pH.
If you use vinegar, the KH will drop and then just return.
The aeration removes the C02 created by the KH and acid to permanently remove it from the water.
Keep going to determine how much HCL you need to get to the desired KH.
Once the water has been aerated and reaches a stable KH (about 24 hours) you can use the water for the aquarium since the HCL is now all used up.
Once you know how much HCL you needed, next time you can just add it all at once.