Since we're spending a lot of time at anchor we're making full use of our water maker. Every day, as the generator auto-starts, I'll run the water maker to replenish our tanks. I like bringing them back to full daily so that we have a buffer in case of a malfunction.
Recently, I noticed that the unit was finding it harder to make fresh water, and I needed more and more pressure and time to start producing salt free water. It was getting difficult to produce enough water, and we were starting to worry about it.
A quick question on the Nordhavn Owners' Group and I got confirmation that our osmosis membranes where likely dead. Luckily all owners who'd been in the region also told me that the best water maker shop and technician in the whole of Mexico was located close to La Paz marina. His shop had installed the excellent water maker and purification system at marina La Paz, one of the few marinas in the area with pure fresh water at the docks. We even had his business card from our earlier stay in the marina.
Luckily, back when I bought Enfin's unit, I chose one that was could be upgraded in the future. The maker of our unit sells a whole line of water makers under the Clearwater name, essentially the same unit with different water making capacities, varying from 400 to 800 gallons a day depending on the sizes and number of osmosis membranes for each model.
One of the most expensive part of the unit, the high pressure water pump, capable of 1000 psi pressure is the same for the whole line, meaning that upgrading to a larger capacity is just a matter of swapping high pressure vessels and membranes for higher capacity ones. No need to upgrade the expensive pump.
A quick chat with our technician confirmed my understanding. Even better, he had the required high pressure vessels and membranes in stock and could start the upgrade the next day.
A couple of guys showed up on time the next day, and started taking out the 2 old 20"membranes, replacing the first one with a larger 40" model then swapping the smaller for a new one. While I had them there, they also changed the high pressure gauge that had been showing signs of laziness, probably due to some debris having made its way into its very thin internal mechanism.
To complete the water upgrade, I also asked them to install a UV lamp I had brought from the US. They made easy and quick work of it so that we now have the added safety of sanitizing our already good water through a UV lamp before it reaches the fresh water pump and is distributed throughout the boat.
The upgrade was a complete success. Not only does our water maker now produce fresh water easily, at very low TDS (Total Dissolved Solids) of around 160 ppm, it also produces significantly more of it than before. Our production has gone up from about 17 to 28 gallons per hour (GPH), which is from about 400 to 650 gallons per day.
The World Health Organization recommends a max TDS of 1,000 ppm, but most water maker manufacturers aim for less than 500. 160ppm is excellent.
The increase in production is not entirely proportional, and actually a little better than pure math would tell you because physics are also involved. Basically pumping through the larger membrane first allows the most efficient membrane to work at its best, with the rest of the untreated sea water continuing on to the second smaller membrane to extract some more fresh water.
It's not as simple as adding each membrane's capacity; the order in which they are put in series also influences the output. This also explains why a 2 membrane system (40 + 20 inches) as we've installed is better than a 3 membranes (20 + 20 + 20) system we could have gone for.
Needless to say we're extremely happy with our upgrade. It's really nice to be able to produce more water, or the same amount of water much faster. We have a lot more flexibility and know that we can get back to full tanks easily whenever we need to use a lot of water for whatever reason.
It wasn't long after our upgrade that we stopped in marina Costa Baja so Di could travel to Puerto Rico to visit her family. The marina touts itself as being top of the line, and in many way it is. It's very pleasant and caters to a very rich clientele of super yachts and larger charter boats.
One thing it advertises, and I got confirmed by the marina office, is that they use a desalination plant to produce water for all users, including the marina slips.
Di first noticed a strong plastic like smell from the dock water when filling up Princess' bowl, and quickly swapped it for water from our tanks. I decided to rinse the hose for a long time, and after a few minutes, the smell was gone so I ended up filling my tanks before heading out to sea to wait for Di's return.
That proved a big mistake, as I discovered soon enough. I had contaminated our tanks with that plastic smell. The water system was under repairs when we arrived at the marina, and I suspect they installed a new pipe somewhere that hasn't yet leeched all its plastic smells?
In any case, I couldn't use the water in my tanks for drinking purposes, and set about to replace it as fast as I could. Which is where our upgraded production capacity came in handy!
Suddenly I had the opposite problem we'd just had: Too much water, that I needed to get rid of before I could replace it with clean fresh water maker produced one.
Of course, I could just have dumped it all, but that seemed seriously wasteful, especially considering we are in a desert. So I did the next best thing: Find all possible uses for my contaminated water. I set out to rinse the boat daily, found every single piece of clothing and bedding that could do with a wash and ran many washing machines, took long delicious showers, shampooed Princess (she gets washed once a year, whether she needs it or not!).
Slowly, day after day, I ended up replacing the water in our tanks twice before I finally got rid of the plastic smell. In the meantime I used the water maker's sampling line to fill drinking bottles so Princess and I could have good clean tasting water to drink.
All is well that ends well on the fresh water front. Upgraded water maker, clean fresh water in our tanks, I can stay our at anchor for as long as I need. Or at least until Di comes back from Puerto Rico.