ive had a 404 running 24/7 for over 5or6 years i belive... not a single problem yet, and its run on fresh and salt. primes easy if you ask me... i didnt know you could break them, ive stood on them to reach something and i think you could almost run them over with a big truck without problem. At the same time i wont highly recommend them as i am a sump man myself. i think they would be great on a 33gallon fresh tank
not any bigger though.