water GH level decreasing
I have tested my shrimp tank water and it has GH level of 5 yesterday. However, when I re-rested it this morning, the GH drops to 3. My tank is a planted tank (not heavily planted)
It has happen to me many times in the past. It seems like my water GH level is always decreasing. Because I am using purified soft water, I have to keep topping up with hard water to maintain its GH.
Do any of friends here in the forum experience a similar problem?
I always the sample of water for testing from the surface. Would that effect my reading? when I kept adding hard water, I don't want to create a gradient of GH level in my tank with highest GH at the bottom....
It would be very grateful if I can hear some suggestions from you guys!