When I began looking for the sand I finally settled on I experimented. I found if the grain size got below a certain point, I was vaccuming up sand trying to suck up heavier poop and debris. If I reduced the siphon size to slow the flow so the sand would not be sucked up, I could not suck up the poop etc.
Does this happen with the sand you use?
I ended up using the CaribSea Torpedo Beach sand. I was led to it by the Admin. of the Finarama site for wild angels. I was getting into keeping Altums and he had been to most of the rivers where Altums are found. He said the Torpedo beach in tanks look the most like what he had seen in the wild. Years back DrsFosterSmith (now LiveAquaria) had summer sales with free shipping and they allowed heavy weight items to be included, Over two or three summers I bought a lot of this sand for really good prices delivered. Back then online sales did not charge sales tax.