I was given a biorb 30l tank today but there are parts missing. I'm wondering if anyone has one and can tell me what I'm missing? I have the halogen light fixture but not the ring that houses it, I have the bubble tube, the filter housing with sponge, and a few unknown bits of plastic with suckers... I need to get the pump. How does the filter work on this thing? I've never had one, nor did I want one, but I don't turn down a freebie!