@Takumi, I wish I could...."Just Do It"... (as that famous logo says). But my tap water isn't really condusive to Discus.
sorry for the late reply .. work has been hectic ... I actually had a problem with the water recently but i did something dumb. I have a 225 litre tank (upgrade ready - waiting to sell old tank) I do 25 litres in the morning and 50 litres in the afternoon.