I got a 125gal african tank and what I "try" to do is a 25% water change weekly but I usually end up doing 50% bi weekly. And my method is I will use the old small hose and bucked method to spot clean the sand and what ever poop I can see on the Rocks and in the corners, for about a bucket or two = 5 min. then I take out the big hose and run it into my bathtub and let gravity take out the water. sit back pound a beer or two watch tv. Then after taking out the desired amout I hook the hose up to the sink (with a ghetto made rig) and I fill the tank back up at the same time adding my dechlorinator and re salting. A total of 40 min with 10 min actual work. I re arrange my rock pretty frequently every 3-4 weeks, cuz Its like having a new tank every month and its a whole new world for the fish lol, but It gives me a good chance to spot clean between them, and yes I actually do find a significant amount of poop between the rocks. I have Lace rock with lots of holes to trap the waste. what kind of rock do you have screaminleeman?
But honestly I would say 80% of the waste I find pilled up between the rocks is from my doo doo machine pleco. He cranks out the crap like hes getting paid for it, and business is booming. lol