For iron filtration, I'm using a 1.5 cuft BIRM filter and Fleck 7000sxt valve. Lately, my well/pump has been running low on pressure towards the end of the backwash/rinse cycle, and I am concerned I may no longer have the flow necessary to properly backwash the filter. Can I shorten the duration of the cycle(s) and increase the frequency so that I do not overdraw my well and therefore maintain sufficient flow/pressure during the entire backwash cycle?

Currently, the valve is set on the dF2b cycle, 14 minutes for 1st backwash, 10 minutes for draw, 0 minutes for 2nd backwash, and 12 minutes of fast rinse. The frequency of backwashing is once every 3 days. We have a shallow well and live on a sandy island. Our pump and storage tank (~120 gallons) normally maintain 45-55 psi of pressure through all our household water use; but, lately, towards the end of the backwash, the pressure dips around 30 psi and water flow through the pump sounds intermittent.

I'm not opposed to reducing the cycle duration and backwashing every day if this prevents overdrawing the well and losing flow at the end of a cycle, but -being a novice- I am not sure whether a short-duration/frequent backwash would be effective.

Any advice that may point me in the right direction, or am I simply at the mercy of our ever-changing water table?
Thanks in advance!