PH low, Gh very high

[Crispywasps]

Hi

My ph is hanging around 6.6, but my Gh is off the scale (takes 16 drops of Gh testing fluid to change colour). I've tried a couple of different tests and they all come out really high. I've also tested the tap water and that's really high too.

I opted for an RO filter and this is testing low for Gh BUT obviously the ph is testing low too. The api test kit is showing 6 but that's as low as it gets. I'd planned to mix the RO with tap water to get the hardness right, but I'd need at least a 50/50 RO to tap ratio to keep the Gh within range, which will throw my ph right down.

Should I just add ph+ to the water during water changes?

 

[Caliban07]

No. But you can add anything that adds carbonates. Oyster grit, crushed coral, cuttlebone, dolomite, potassium bicarbonate.