re: Just got back into saltwater aquariums. got sick deal

I can help a little. The "live rock" you have can be jump started with a few more pieces of rock from a local pet store. That would be the best way to do it. Depending on how many pounds you buy, it may take a little while, but it will happen. You can also use some live sand to help jump start the rock. I would add the new rock to the container that you are using now with the skimmer running and no lights. The rock you buy from the pet store will likely need curing.

As far as the sump, It's a great place to store your heater. When I had mine set up, I had a small light on it. I had a few pounds of live rock in it along with some caulerpa plants and a mangrove tree. The mangrove tree will help eliminate excessive nutrients (plus it's just cool to have one growing down there.) The caulpera should grow really well down there. It also uses nutrients that helps clean the main tank. You can also harvest it to remove nutrients and even some local pet stores may buy it off of you. Make sure you have a few turbo snails and blue legged hermit crabs in the sump to keep the algae under control. The sump will be a great place for copepods to grow and will eventually make it into your main tank. Corals and fish will feed on them.

One more thing, to help stabilize the ph, have the sump light on a timer and set it to come on when your main tank lights go off and vice versa.