Been working on ideas for filtration for my 320, was going to go with a 55 gallon sump and an fx5 but I built my stand a little to short for comfort. My tank is against a wall to a spare room not in use so I decided to run the pipes through the wall into the spare room. This gives me the option to run a 55 gallon drum fluidized moving bed with K1. I would make something to support mechanical filtration before entering the K1. I was looking for a cheap sump I could plumb it into to keep about 100 goldfish, heaters and pump. I watched the video with the 375 fiberglass tub with the barrel in it and wanted to go along that route. I can't find any used fiberglass tanks around that size in my area so im looking for alternatives. I would like 100 gallon if the drum is not inside it. I will probably use this to filter my 125 as well, open to ideas and suggestions. will be running a drip system as well in both tanks