Yes. The BMSA7S is compatible with the BMS1225 .
Just cut out a piece from a can and drill a hole to replace it. I bought one shelf and cut out a piece of wood for the second shelf. Worked fine.
The BMSA7S is compatible with the BMS1250 and the BMS1250SB .
The BMSA7S is not compatible with the BMS5700 .
It is held in by screws that go thru the 7 tabs. You would need to undo the screws in order to move it.
Please call our contact center at (800)846-2345 and one of our agents will be able to assist you .
They are sold individually
The BMSA7S is not compatible with the BMS7702 .
You can custom make one but I found it easier to buy the shelves and save time as the shelves aren’t rectangular. Also the shelves I bought are very sturdy I put all my pool chemicals in it and no sag
Maybe Home Depot customer service can help.