Pump Interchangeable With Micro Star Clear

I am using a micro star clear pump/filter system for a flotation tank that I have in my basement.  I now have two complete micro star clear units that I purchased so I could easily swap one out for the other when I need to have the pump rebuilt which needs to be done yearly due to the Epsom salt eating away at the seals. I've hard piped and glued the whole thing with the exception of the outlet from the pump into the threaded bent tube that leads to the filter.  Leaks here have always been my nemesis.  I now have two pumps that need to be rebuilt, a collection of motors, and at least one filter that I can't for the life of me get the top off of.  I'm thinking about upgrading to an Easy Clear system since I like the looks of the design better.  The manual lists an SP-1575-1 pump, but the same manual is for both the 1540 and 1575 models.  I'd like to know if I can use any of my old motors/pumps/filter baskets in my inventory to use as a quick switch when I have the pump rebuilt, so I can always keep things operational.  I'd like to go with the C-400-1540LSH model which has the same flow rate as my micro star clear(20gpm) (I’m only dealing with about 170 gallons of water, but the solution has a specific gravity of about 1.28….I’m running the output through a pond UV unit for sterilization before returning the solution to the tank and need to keep the flow rate to a minimum) The Micro Star Clear pumps that I have are SP1540-CLS.  What can you tell me?