Water Chemistry

[kevo]

Hi, everyone, can anybody help. I've tested my tank water and I need to lower the GH hardness But not the PH or KH. The actual readings are
PH 7.5
GH 240mg/l (ppm)
KH 70 mg/l (ppm)
as you can see my water is very hard but the ph is about right for the fish I have, which are
2 Burnished gold marble Angels
3 Silver sharks
1 Ruby shark
1 Pleco
1 Male powder blue gourami
1 Upside down cat
How do I drop the hardness but not the PH
any help appreciated.
Thanks.

 

[CFC]

The safest and easiest way to reduce the hardness of tank water is to use R/O water for water changes. To obtain R/O water you can either find a lfs that sells it (usually around 15 pence a litre) or invest in a small R/O unit, prices of which start at around £70. R/O water has a pH of 7 and is so pure that the trace minerals have to be added back to make it stable, this means you can tailor your water to the exact requirements of your fish by varying the ammounts of minerals and buffers you add back.

Messing about with the chemistry of the water in your tank with chemicals isnt recomended as constantly changing water parameters will stress the fish and lead to disease outbreaks and deaths.