Mould

I went to feed my plants today and noticed there is white fuzzy mould growing on the top of the coco, there is a little bit that has developed on the base of the stem on 1 of the plants. The humidity usually stays at 65% but sometimes creeps up to the early 70s for some time. Temperature fluctuates at 20-25°C. I've also noticed that one leaf is covered in brown/orange spots, a couple of my other plants have these but not with the same quantity. Any help would be appreciated.

Thats pumice bro, it comes in the coco+. It just gradually rises to the top each time you water

Mold is fine it will die off when the surface drys. The rusty spots are probably a calcium deficiency.

I see it now sorry. Yeah I feel stupid