My question is where do i begin? how do i know what size pump to use? and should i just by a over flow? then with this tank sump now, what do i use in there as far as filtration?
I would first suggest you read our article on what a sump is. Just to make sure you have a good understanding of the basics. You would size the pump using a few factors. First the height the pump has to push the water up to the display tank. Each pump will be affected by head pressure differently so knowing how much the GPH
dropps off at 3' or 4' is important. Second you need to know the max capacity of your drain lines in the main tank. If your main tank is not drilled and it sounds like yours is not then you have two options. (1 get your tank drilled, 2 purchase a hang on overflow). If you purchase a hang on overflow the overflow will have a max rated capacity. This max capacity needs to be observed when getting a pump. You want to make sure the pump does NOT push more water at the head height your gong to have than your overflow can process. If the pump does push more water then you will have a problem with the main tank filling faster than the overflow can empty the water back to the sump.
As far as filtration you would use the same level of filtration you have now. A sump is simply an extra water storage vessle where you can put your skimmer, heater and other accessories like UV
reactor, etc. If you want you can drop a few lbs of LR
in the sump and just increase your LR