Rust covering rocks

[paddyob]

I agree. cycle. possible diatom Outbreak. are there bubbles under the slime? dont scrape it either way. probably whats clouding the water. should clear on its own in a week or so if cycling.

[jassz]

It doesn't look like slime. It looks like a layer of rust coloured 'dust' lying on the rocks. I can't see any bubbles either.

If I'm having a cycle, how often should I check the water parameters?

[paddyob]

Originally Posted by jassz

It doesn't look like slime. It looks like a layer of rust coloured 'dust' lying on the rocks. I can't see any bubbles either.

If I'm having a cycle, how often should I check the water parameters?

Thats a matter of opinion. i would say once a week, with a small water change after. if your levels are wonky It will possibly add to the issue. could be simply a cyano Outbreak. let your tank go for a couple weeks. should be fine. would not worry.