Buffer And Salt Question

[Faythee]

I have high PH tapwater and didn't have an issue at first but my numbers are dropping in the tank. Currently 7.8-8.0 ph, GH 9, and KH 6

I picked up Seachem liquid buffer as well as the cichlid lake salt.

http/www.seachem.com/Products/product_pages/L_TanganyikaBuffer.html

After researching I found they say the directions are based on RO water. Now I am afraid to use it. Should I just put a couple capfuls in each day until the numbers get closer to where there should be ? It is a 56 U.S. gallon.

Also, as far as the salts go.....I do not know what minerals, etc. are already in my tapwater. Should I just skip it or maybe half dose ?

I currently have Yellow Labs, a Calvus, and a Lelupi in the tank.

Thanks !