When your mg low, it will be hard to maintain your other paras like ca & kh. Need to buffer up to at least 1200mg/l if not u will alway have problem keeping ca and kh levels stable.
No use, try many places low flow still fly away. Now place in a small cup with a small rock in my sump. Now some of the rics starting to stick to the rock. Hopefully it will do the trick.