'91 V20 Fishbox Question

[2ndCurse]

Sorry, my question was a little confusing. What I can't figure out(until I pull the soft gas tank cover) is how the infloor fish box is plumbed. I would assume that the brass fishbox drain went to the brass thruhull at the waterline and the plastic drain went to the plastic thruhull next to the bilge pump thruhull. If that's the case it would reuire a pump because it's higher than the fishbox. The brass thruhull is at the waterline. 2 things confuse me, when I cleaned the bilge it backed up into the fishbox, and I don't have a switch for a pump that I would certainly need on the other drain. I guess I need to get under there and make sure I don't have a hose off, and an open thruhull. Any input? Thanks