We are relatively new to reefing and have gone all in with a Waterbox 220.6. We've decided moving forward to set up our own quarantine tank. My question is about the size/dimensions. In others experience, what is the best size/setup? 20 gallon? 29 gallon? Long vs tall? Any other tidbits of knowledge would be helpful! We plan to get our fish small, but want flexibility in the event that an older fish down the road needs to be quarantined. Thanks!