After reviewing the procedure I used to change the pump, there are a couple of thinks I would do differently than described here that I thought I'd share.
When marking the bottom for the cut, instead of using a marker, I would start by first lightly scoring the 4 lines using a razor knife and straightedge. At the 4 corners, I would then drill a 3mm (1/8") hole to define the line ends. Finally I would heavily score the lines in order to create a positive groove to follow with a cut-off wheel or end-cutter tool. This would leave a cleaner cut with protection from going too far to the sides.
The other is that I was uncomfortable in having to totally reassemble and seal the unit to be able to test it especially if I am not using the OEM pump. Once the pump is installed, the unit can be temporarily tested by placing in on a structural foam board or dense foam pad placed in a dish pan/washing tray which can hold at least 2 gals (8 l) and weighted down or clamped with bar clamps. This will allow it to be filled with minimal leakage yet still be able to have the power cord safely attached to test. Once the test is completed, simply unplugging and lifting the unit drains it with the advantage of getting rid of any left over cuttings or debris. This technique would let me test more than one pump with minimal setup.
When marking the bottom for the cut, instead of using a marker, I would start by first lightly scoring the 4 lines using a razor knife and straightedge. At the 4 corners, I would then drill a 3mm (1/8") hole to define the line ends. Finally I would heavily score the lines in order to create a positive groove to follow with a cut-off wheel or end-cutter tool. This would leave a cleaner cut with protection from going too far to the sides.
The other is that I was uncomfortable in having to totally reassemble and seal the unit to be able to test it especially if I am not using the OEM pump. Once the pump is installed, the unit can be temporarily tested by placing in on a structural foam board or dense foam pad placed in a dish pan/washing tray which can hold at least 2 gals (8 l) and weighted down or clamped with bar clamps. This will allow it to be filled with minimal leakage yet still be able to have the power cord safely attached to test. Once the test is completed, simply unplugging and lifting the unit drains it with the advantage of getting rid of any left over cuttings or debris. This technique would let me test more than one pump with minimal setup.