I have about 6 fluvals in my possession. They are very handy. 2 404s on my 70 FW
and the others I use for various SW
tasks. I can use the 104 as a vaccuum to clean LR
. I put phosban in the 204 and have a 304 on my 33gal solana for some real filtration. The only issue I have had was when I left the valve closed for who knows how long. When I opened it, it dumped a quart of sulphuric acid into the tank, killing my flame angel pretty quickly.