Don't need a tank. It may help your sale if you can tell people whether the inside is clean or not. The reason I changed my tank on the Demon was that it had junk on the inside that I could not remove. Had it come loose in use, it may have opened a hole or may have been sucked into the pickup sock. If someone had a tank at that was clean inside, at your price and other conditions you have stated, I would have bought it.