How to mix my tap water and osmos water

[Edlund]

Hey there i have a little problem with my water.My Tap water is: Ph 7,8 kh 2,
gh 3 and Us 200. I mix my osmos 70% with tap water 20% and add 10-12g mineral salt but the Ph is the same and i want it down to 6,5 and the kh 4 gh 4 and Us 60-80.I dont know to get it right.U have som idea u are most welcome to help me :)

[RandalB]

Sounds like you don't need RO to me....

100PPM TDS with those parameters sound just fine for breeding or keeping.

RandalB

[Alight]

Why are you using RO water? Your GH and KH look OK for Discus as they are. The pH is not out of line, and will come down, even if you change 70% of your water daily.

I'd suggest not using the RO water. It actually looks like your RO unit may not be working properly--check it. It should be essentially 0 GH and 0 KH. This means that if you just mixed your tap water and RO water 30:70, should have a GH of 1 and a KH less than 1. Your pH will be nearly the same as your tap water, as RO water has no buffering capacity.

I'n not suggesting you do this, but the only way to bring your pH down is to add acid of some sort. This can be done with CO2 injection (carbonic acid) or by adding a mineral acid of some sort.

I really think your tap water will work fine, and you'll end up with water around 6.4 if you change 50% of your water daily, and have 1 adult or Juvi Discus per 10 gallons of water. The Discus will add the acid in the form of nitric acid from the nitrification processing of their waste.