Hello Wolfgang, my name is Jean-Pierre and Eleuthera is in refit in Turkey. She should be complete mid March.
My previous boat had a desalinator and it worked well. There is only 1 secret about these units: use them often and rinse them well after use. If you don't use it for a long period, you must pickle the unit as per the manufacturer's instructions.
I had a 25 l/hr on Eleuthera and one aspect of the refit was to replace it with a Dessalator DUO 100 from Dessalator. (This is the brand still in use by Amel in their newest boats.) It is a dual voltage system allowing water production off the 24 V DC system or from the Genset/Generators through either direct from Genset or from the Inverter.
The house bank is made of 8 batteries... ! (1200A) and we have a 500W solar array built into a nice gantry. Nice place to have the dinghy when at anchor.
We expect to be in the Caribbean around Dec 15/ Jan 16. If you are still in CR, we'll pay you a visit :-)