Oh, boy....now they've made it even MORE difficult???
When one 5 gal. bucket sits down inside another 5 gal. bucket(or smaller size buckets of the same size), the bottom bucket has about 6 in. of empty space. This reservoir will hold the liquids from your top bucket. When you add plain ol' water to the top bucket, the water filters down through your feed and adds to the hyper fermented water in the bottom reservoir. As it mixes, it rises in level into the feed in the top bucket through the holes in the bottom and sides of the top bucket. This disperses the fermented water throughout the feed in the top bucket. THIS is the backslop....you are using the same fermented cultures throughout all the time you are fermenting and this can go on for as long as you want without changing out that water in the bottom.
The residue and powdered feed stuff from your feed mix will settle into the bottom of the bottom bucket and the cultures there will feed on each new infusion of these particles. This keeps your cultures from dying and letting bad bacteria grow, so this can go on and on and on without every changing out your fermented water. In other words, you only have to use ACV one time...ever..for your feed mix.
You don't have to even move these buckets one from another, you just adjust your liquids if you don't want to have to strain off. You don't have to pour anything into that top bucket except plain water when you add fresh feed...and just add enough for your consistency wants.
It's really, really simple and only takes mere seconds each day to tend to or dip out the mix for feeding.