I've been doaseing awhile now Tom and have found keeping the end of the hose's out of the water helps allot and I also keep the doaser above the water line of the sump and try to keep the lines straight as I can and pointing down hill.I haven't had any build up issues since doing this. I also have a profalux 4 doaser I'm not useing if your looking for a sweet deal.(far supior to the magnus) Hope this helps