Based on what you have said so far you could.
I need to add a couple 50 lb bags of Calcite to my system. What do I need to know about backwashing? I'm not sure how to do it -- don't recall if the installer ever mentioned it. I don't believe I have an automatic system. I have a top-flow tank with no electronic controls at the top. Other than shutting valves and funneling in the bags, what do I need to know about backwashing? Thanks in advance.
You have an upflow filter meaning there is no control valve so the water goes down the distributor tube and up through the mineral and out to the fixtures. So you need to run water somewhere other than in a septic tank to get rid of any discolored water after refilling the tank with new mineral.