I just redid my rock work and major cleaning. and the sand is full of dirt. It needs a vac. the tanks been running for about 15 years. It's been about 3 years since my last major cleaning. TO VAC OR NOT TO VAC THAT IS THE QUESTION.
I use to, but I stepped on the tube of my gravel cleaner and smashed it. I also read to leave sand bed alone. My sand beds about 1 1/2 to 2 in. Full of dark gray crud.