Wilmdale writes:

I am using a Sequence pump. So far so good! Quiet, powerful
....
Much to my surprise when I was having trouble with the priming pot I
purchased from them through AZ Ponds, the people at MDM, Inc., responded
promptly to my e-mail

I bought my sequence pump from AZ about 10 years ago, they had the lowest price
at the time. Years later when I was curious about the pressure/flow
characteristics of the pump I was dismayed to find it discontinued and not on
MDM's website. I emailed MDM and though it took 2 weeks, they emailed me the
pdf spec sheet for my pump.

I recommend both companies!