Looking to breed my Discus using RO/DI system

[LostInFish]

I just bought this system. So I'm new to the PH,GH,KH basically new to RO and how it changes my chemicals. It produces a ph6 gh0-1 kh0-1 when I mix 10/1 ratio with tap water it gives me PH 6.8 gh7 kh5 any ideas on how lower gh only maybe PH to but not kh

 

[LostInFish]

Here is a pic of the breeding Trio

 

[LostInFish]

So I got my ph down to 6.4 gh5 kh5 so far all is good I've had to use acid regulator to lower ph because RO wasn't enough at 10:1 tap water. So I use enough acid regulator and neutral regulator to stabilize the ph at a low 6.4 only down fall is my TDS readings are high now along with my phosphates that have doubled no algae prob or nothing yet nock on wood doing daily water changes