I have a plexi tank now. Have only added 1 or 2 scratches in about 5 yrs, but the sides look cloudy, so I guess I've done well with it. The story of my tanks is this. My 40 is getting too small, yes, it's shrinking. I was given a 50 ga corner pentagon tank on CL with PCs, stand and canopy. But the only corner in my living room has my big hunking TV. So the free aquarium would probably cost me thousands for a new flatscreen for the mantle. That tank would give me some more room, especially if I don't use a DSB, plus it has no internal overflow. So I need to decide whether to set up this tank or buy a larger 72 or 90 ga used tank. I can't afford a new tank and stand etc. Decisions, decisions. Any suggestions from your experiences?