I went 5 months without cleaning mine. I started doing wc's out of the sump because I moved my clam to the top of the reef. When I did the first wc with the clam at the top, he spit water across the living room. I had to put a towel up so he wouldn't get the floor any wetter. With this new method everything stays wet and happy... except the carpet. I do a 30 gallon wc every two weeks out of the sump. I turn off the pumps and leave the Tunze and lights on. I scrub the sump and add new water. This way the corals are never the wiser. It's a pain, but they seem to love it! I am a sucker for happy corals. LOL!
I have a lot of detritus collecting in my sump so I siphon that out when doing water changes. My current system has been up for 18 months and I have never cleaned it more than that.
I clean my refugium every few weeks, but the sump is clean as far as I can tell. Well I do swap out the filtersock every week so I guess that counts as cleaning weekly.
i clean mine out with a hose pipe every 2 weeks with my water change. I drain the tank of the water,,,then get the hose pipe and flush all the crap out. then i fill the sump back up with premade salt water and let the system back on. the beauty of having a sump in the garage...i love it...
If I don't clean the sponges "The Dead Ones" Then my sump will over flow because the only way for the water to go through it is through the sponges. But since I got my Euro Reef I don't have to do it as often.