those sponges are supermarket, kitchen or toilet cleaning ones? DO NOT USE THEM!! Most come impregnated with detergents and ****...the risk of destroying all your fish and filter media is enormous. Throw it all away! Believe me.
im telling you and others are too, DONT USE THE SPONGES!!!!!!!!!!!!!!!!!!! just use pot scrubbers like you have. and the filter floss or your mechanical filtration should come first, so put it in the top bin. you want clean water to trickle over the bio so it doesnt get gunked up.
yeah i think you need to tweak your setup a bit and get rid of those sponges ive herd of sponges dissolving when in the water and not only that they could have detergents in them like someone said also the mecanical filtration needs to be first then the scrubbies should be second and then im not sure what to put in the third bin maybe more scrubbies? idk just not sponges