I have two March May pumps, both of which were sourced via ebay.  The MMP3 (on the left) is used as my HERMS pump, this can pump fluid up to 80ºC so can cope with mash temperature, the other pump (an 809 I think) can pump boiling fluids so this is used for circulating the water in the HLT and for sparging.

Both pumps are magnetically coupled which allows me to restrict the output flow without stressing the pump.  To control the flow a ball valve is connected to the outlet of each pump. Setting the flow for sparging can be a little tricky as the flow rate needs to match the output from the mash tun. This I try to set to approx 0.5L /min.