Should I remove my shallow sand bed - issues in tank

[Myka]

I use vinegar in kalkwasser and add it through a doser. I don't use it for nutrient lowering reasons, I use it to make the kalk more concentrated. It definitely affects the PO4 and NO3. That's an option too. I dose BioDigest as well. Biopellets I think are simpler and easier for long-term.