Does a protein skimmer use up more water?

[jassz]

All right, I'm more than I little confused. I thought having proper filtration and ripe media were an absolute MUST for an aquarium. You're telling me I don't need either? What filters the water then?

I have had the tank since May 2, and was just starting to wonder when/how I should do filter maintenace on the Fluval. It was going to be my goal for this weekend. I had a vague idea what I should do there, but now even my vague idea is out the window. ACK!

Also, what is kalk? I can see how evaporation affect salinity, but I can't follow the issue with pH dropping. BTW, my pH has always been 7.8... is that too low?

Thanks,