Little white things in Sump?

Over the last couple of months I seem to have aquired a couple thousand little white things in my sump tank.

They are attached to almost everything, the glass, the partitions, inside the protein skimmer, the pump...everywhere. I have attached a pic, it's not very clear and I will try and get a better one if no-one can see it properly.

I get the odd 1 or 2 appear here and there in the main tank but I assume the livestock keep them down, does anyone know what they are, and if so can i just leave them to it and not worry??

Many thanks

Here's the pic, didn't seem to attach to the last post

Thanks for the reply, good to know I don't have to try and get them all out, that would be a real pain...although I'm still not happy about them being inside the protein skimmer.

I will hope for the best