Thanks Reiverix!
I did a big waterchange yesterday to flush everything out, and today I dosed just 1/16 KNO3 and 0,3 ml TMG.
No KH2PO4.
No KH or Ca-additions either, because our tapwater is very hard, 16 dH, with a lot of Ca. Hehe, I still see - after 24 hours - a lot of small particles of Calcium from the saltmix on the rocks and sand - who knew our water was so hard that it's hard for Ca in saltmix to mix with our water.
