Isotherm Indel Webasto refrigeration

[MIRELOS]

I've had nothing but problems with the refrigeration on the boat, bought new in France at FP. I have 3 Compact Magnum units; one for the refrigeration and two fro the freezer. I do not understand why Indel Webasto uses pumps that are for fresh water when this is a blue water boat, I keep replacing parts and I'm getting to the point where it might be cheaper to purchase other make units, however the parts people and the tech support including a very helpful member at CF advise that I plump the system to my water tanks, the water tanks are at least 25-30 feet away from the compressors. I suppose I can tap into the outdoor shower line for intake but how do I return the water to the tank. The only entry lines are either the deck fills or the fill/switch valve from the shore line connection.
I have connected one of the units to a 6 gallon tank and it works great but I don't want to add the weight of two more tanks in one spot.
Any suggestions would be most appreciated.
Carlos
s/v Mirelos

[double u]

surprised abt. this: the parts of the pumps in touch with water are all plastic, so fresh or saltwater shouldn't matter.
having freshwater from the on-board tank go round through the system sounds crazy to me - it has to retain drinking-water quality!

[MIRELOS]

After many conversations with the pump manufacturer Pentair/Shurflo, it makes a great difference. I have replaced four pumps in four years, Pentair was great in sending me the pump that they recommended and it is so far working great; it is quieter and takes to the voltage variations better......of course only time will tell.
Some boats in particular custom boats have the water from the tanks recirculating, it was also recommended by Indel Webasto for my particular problem, but the run is too long on my boat.
I don't drink the water from the fresh water tanks unless I boil it and or filter it first, so that would not be a problem.