I have a 180 gallon fish only tank. Has been up for 15 yrs now. I have been somewhat negligent in my maintenance as it has been very stable. I have a large spiny puffer (8"), a cubicus boxfish who is blind from popeye (8"), a tomato clown (very aggressive), a blue tang who is at least 16yrs old and a naso tang so total of 6 fish. I have a wet dry filter and have honestly never cleaned the bioballs. The do have a moderate amount of brownish goo on them and I am not sure how to clean them. If I clean them all at once I am worried I could lose my biological filter. I do have a good protein skimmer also. Any advice would be appreciated.
I have quite a lot of live rock, not sure how much in pounds but it covers about 1/2 of the back wall of the tank, (tank is 6 foot long). Yes I thought about cleaning them in the old tank water rather than fresh water. I assume the fresh water would kill any bacteria on bioballs