Fuge maintenance - how often do you vacuum/clean-up?

[Subsea]

I have not cleaned my sump in 25 years. I bought system used as a miracle mud / macro refugium. In 25 years, mud depth has increased by 3/4” with spongy mud crawling with worms. Five years ago, I turned out the lights and composted tomatoes with macro and added live rock with cryptic sponges. I now have a cryptic refugium as a zooplankton generator and a DOC recycling zone.

 

[Mark Gray]

My current tank is almost 6 years old, I have cut some Cheeto out of it but haven't done anything else. I move a lot of water through it. I have tons of pods and tons of worms in there and Fiji mud in the bottom

 

[Spare time]

Every few months I siphon the bottom. Otherwise I can get a big dirty spillover into the tank when I flip or remove macroalgae. I also dose bacteria to help eat sludge so that might help too.

 

[myrjon]

My sump is a 40 gallon tank (2014) never cleaned sand or rocks . Every time i move something in refug part ,water is really dirty .And then I run floss .Should i rip down and totally clean .Add new sand? My question is wouldn't this cause a new cycle? Seen some people that do not ?