I also use the Remora. I could go a week without emptying the cup, but I also clean it more often, because production drops off when the neck is gunked up. I use the bottle brush through the nozzle (this is the white screw) about monthly, at least. I notice a difference when I do this.
When I clean with muriatic acid, I use a 4:1 ratio, but definitely outside, in the dirt. That stuff will etch concrete. I usually let it run for a few minutes, just because. MA works extremely quickly. Afterward, I rinse out the skimmer with the garden hose thoroughly. Next, I fill the bucket that had MA in it, with the garden hose and run the skimmer for a few minutes with the hose running in the bucket, constantly overflowing the bucket.
I only do this a couple times per year. When I do, I notice production skyrockets, but it's extremely wet and clear. Typically, I have to raise the cup WAY up for a couple weeks while it settles back down. Most of the time, I run my collection cup as wet (low) as it goes, without even using the rubber band.