We use mixers in our tank. Causes solids to build into a funnel into the sump. Mixers look alot like small electric outboard motors with propellers.
you do not say what the composition of the cake....i have use hp water hot if possible.....with rotating head....if waxy..little greaser type product..
Sink a pipe in the bottom of tank with holes drilled in it .Apply air pressure at adjustable air flow. Problem solved.