How To Change Water Hardness?


I currently have 3 mollies in my aquarium.
However, the water seems to be a bit more on the softer side and I am starting to see that it may be taking a toll on the fish, I think I am beginning to see the shimmies in one of them and would like to better the aquarium conditions ASAP.
What are some suggestions to harden the water a bit? TIA.

NO3: 40
NO2: 3
pH: 7.5
KH: 40
GH: 60
Temp avg.: 78F.

I am somewhat of a beginner in keeping fish so please let me know whether these readings are acceptable for mollies or not. Any suggestions for how to better the water quality is more than welcome, thank you.


Read Beginners Guide to Aquarium Carbonate Hardness (KH). This will help you along.


U can use calcarean rocks or shells to up the kh and gh, or sodium bicarbobate to only up the kh.
To only up the gh, use calcium chloride and magnesium chloride.


Yes, I think it should be higher for mollies.

I'm also about to start slowly increasing GH as it's lower than I'd like for my fish. My tanks are currently 4-6 dGH (I think that's 71-107 ppm).

I ordered this GH Booster booster yesterday; it's from the company that makes Thrive fertilizers. I was already ordering ferts from their website and it's $8 flat shipping per order so I figured I'd give it a try. It's magnesium sulfate, potassium sulfate, and calcium sulfate.


Some just add a small bag of crushed coral to their filter ..

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