Of course if you have a dirty sump you have to clean it first from all that detritus.
Once clean add a pump of some sort and you never need to clean again.
I don't run socks and have the water moved by a pump for about 10 years now I have a white bottom sump and it's still white.
Than again I need all the nutrients I can get back into my tank as if I don't feed for a day my Po4 is undetectable and if no dose of No3 is applied I will drop down to 1ppm or lower in that same day.
Not all tanks are the same of course but putting it back into the system works for me.
Oh did I mention I dose skimmate on weekly schedule too