I replace the Caleda pump about 5 years ago based on a recommendation by Coastal Climate Control (the US Climma distributor). This is the pump I have:
It is rated at 1620 GPH 50htz and 1800 GPH 60htz, ample to run all three ACunits in series.
The cost of the pump is about US$600. They are sold all over the world as are replacement parts. I prefer this design over the Calpeda because it doesn’t have the expensive bronze impeller and there is no metal in contact with sea-water. The March pump has a magnetic drive and plastic (polypropylene) head. However, the pump hasn’t fared well and the exterior screws on the pump end (not the impeller housing) have rusted a little bit as did the capacitor cover (since changed on the newer models). I have to treat the pump with some Corrosion X periodically. This seems to work well. Perhaps the newer ones are more engine-room compatible.
With best regards,
Sailing Vessel - Cream Puff - SM2K - #275
Currently cruising - Tahiti, French Polynesia