watermaker ppm

That's about right, 200 is about as good as an RO can do and anything under 500 is good enough. You aren't going to get great water from an RO but it is not going to hurt you as long as you have clean feed.

Hi,

While to the best of my knowledge the two items listed below will not be required by legislation on a boat like yours, if you are concerned about the quality of the water you are supplying your family/friends/guests then:-

You could also look at adding silver ionisation or chlorine dosing to the filling lines to the tanks but not both together.

UV Sterilisation is also good to use on the consumer side of things of using RO Water for domestic consumption.

Hi,

PPM is only one part of water treatment.

The two things I suggested treat the other things that can be found in "home-made" water.

The water made and stored onboard can carry a number of harmful bacteria in it that are not removed by filtration.

I would say that where you're at is fine. I see mostly 350-450 ppm on a lot of watermakers, some get done into the 200's.

Is it possible for the OP to add the iodine tabs after treatment to assist in killing off any bacteria?

A drop of bleach per gallon of water works.

Just make sure that chlorinated water doesn't get back to the membranes during the fresh water flush cycle.

That is true.....I generally flush the watermaker right after the tank is full, then add the bleach to the tank. But I don't think 1 drop per gallon of water is any stronger than the chlorine in the city water supply that most people fill their tank with.

That is correct but I would not dismiss waterborne bacteria so flippantly myself.

You are partly correct, how correct depends upon your definition of "bad".

A low flow of product water can be attributed to a low flow in general caused by blocked filters on the supply side, faults in the HP Pump etc. A reduced output can also be attributed to cold water.

A damaged membrane will allow non pure water to flow to the product side, this will cause a major spike in your PPM count.

Usually low flow, but also can have higher product PPM as well......

Answering only the question that was asked:

The PPM output varies slightly based upon the initial salinity content of the supply water. That said, anywhere in the 300-400 range is about what you will see. I have seen plenty of RO systems that output in the 500 range down in the islands or well off-shore where the initial salinity content is very high.

The addition of a UV light in the treated water circuit will reduce algae formation and, presumably kill cooties as well.

Hi,

It depends upon what you call the treated water circuit in this case it seems the only treatment the water will get on it's way to the consumer is a push through the membranes, a soak in the onboard bacteria growth arena and then away to end user via a quick re orientation in the pump.

BTW: UV Sterilisation is not a permanent sterilisation method.

"Treated water circuit" is a fancy way of saying "Hose leading from the RO machine to the FW tank. A fairly typical installation can be seen on larger vessels where the tell-tale blue UV light can be seen in-line through a clear section, to make certain the light is indeed on. UV [see link] is proven and sold as a method to kill viruses, bacteria, microorganisms (ie., "cooties").


http://www.pure-aqua.com/uv-sterilizers.html

Hi.

UV is not accepted under any rules and regs I am familiar with as a sterilisation means for water going into storage tanks.

It is accepted for water going to consumers in a circulation type system and there are strict rules covering the dead lengths of pipes.

Water being loaded and made onboard must be pre treated before going to storage on anything I am involved in these days.

Handling and treatment of potable water can be a complex subject and how it is managed depends a lot on flag, class, and port state public health laws.

FWIW and to complicate matters enough to keep the thread alive for a while, curl up with the following docs this evening ...

http://www.uscg.mil/directives/cim/6000-6999/CIM_6240_5.pdf

http://www.med.navy.mil/directives/Pub/5010-6.pdf

http://www.dft.gov.uk/mca/m.1214-3.pdf

http://www.coastguardrescue.org.uk/c4mca/397.pdf (part 2)

Not sure of the rules/regs in your area of the world, but if you check out the specs of any major US marine RO manufacturer, such as Village or Watermakers, Inc, you'll find UV options. I have seen the blue light in action on many yachts here in the US, mostly larger than 80 feet due, I reckon, to the cost involved.