New 55g tank questions

So I have a few questions about setting up my tank I have done quite a bit of resesarch but still have these questions. First I am converting this from a freshwater tank so I have a few things for it already and bought the live rock. At the moment i have about 65 pounds of live rock in the tank with a heater and old filter to circulate the water. I also have a skimmer not a great one it is one of the cheap ones from ebay that I recieved as a gift and so I will atleast try it even though chances are it wont work to well. For lights, right now i have a t8 2 bulb fixture that I would like to try and use I have another of the same exact fixture if I need it but would like to stick with the t8s until i have the money to upgrade but hoping they will work for now. Will they t8s grow any coral, to start off with I just want easy ones like mushrooms and things like that? Next question is about a sump, I would like one but only have room for a 10g is it even worth it to add one that small? Have more questions about stocking the tank but that wont be for a month or two as I have to cycle and get everything going so I will ask those later.

 

My guess is that you will be very much on the low side. Some mushrooms maybe, but not much else.

I would say yes. You can put your heater in there along with an in-sump protein skimmer and other things you'll add in later.