UV sterilizer before fresh water tank.

[sailorboy1]

Originally Posted by oleman

The very large evaporators used do not get the water hot enough for heat sterilization.
.

They did when I ran them!!!

[TheThunderbird]

I drink tank water.

Which %of CL should I use regularly? (I clean tanks with CL annually)

A carbon filter is enough for having a good taste?

[Snore]

The target CL level should be between 0.6 and 4.0 ppm. To get that exact you will need some test strips.

Me? I take shorter trips and (gasp) buy "suit cases" of bottled water with spigots. The purchased water is used for any water drank directly. Cooking and cleaning water comes from the tank. I put "some CL" in the tank every week or so and fully drain the tank every 6 weeks or so.

But there are many ways to reach the same goal.


Sent from my iPhone- please forgive autocorrect errors.

[thinwater]

Originally Posted by EvilRabbit

As we head off to cruise the more exotic locations, I have been thinking a lot about our fresh water. I have ordered an additional UV sterilizer for our watermaker and got me thinking about the rest of the system.

As we filling up at marina's too, I thought about adding an additional UV sterilizer between between the freshwater intake ( where we fill up via hose when we at marinas ) and the tank. This helps prevent any live nasties hanging out in the fresh water tank.

So my water is covered from the watermaker to the tank and also from external sources.

A basic UV filter is super cheap and a 8watt will be more that sufficient to cover the max of 20lt per minute from a tap. I would wire it up so we only switch it on when we filling up.

Thoughts?

You will still need to chlorinate the tank, since if ANY bugs that get past the UV they will reproduce in the tank over time. Also, you will STILL need to pre-filter the to keep the UV clean (any dirt blocks the lamp) and to keep sludge out of the tank (great bug food).

A more standard and well-proven approach...

* Pre-filter (~ 1-5 micron) when filling to get the large particles and prevent sludge and reduce chlorination residuals.
* Chlorinate the tank.
* Post filter with a carbon block (0.5 micron) to get cysts (resistant to chlorine) and remove chlorine taste and residual.
* And put a strainer on the vent to keep insects out of the tank.

You could UV treat at the boat tap. But remember that UV is not very effective on cysts and parasites. Any you still need that pre-filter. Also remember that the UV needs to be left on to provide warm-up time and to keep bugs from growing on the lamp.

[thinwater]

Originally Posted by TheThunderbird

A carbon filter is enough for having a good taste?

Not necessarily. If the water gets skunky from sulfate or certain other contaminants, the chlorine removes that better than carbon, and then the carbon remove the chlorine. It is a 2-step process.

[topmast]

Some skippers are a bit more casual when it come to fresh water aboard. Crewed on a cat in India. A lot of ice (from shore) kept the beer cold and then transfered to tanks. I went wha?? and was shown the UV tube under the galley sink. No problem, I'm told. Didn't quite work out so good though but shows there's a lot of leeway in designing your system.

[nigelmercier]

It isn't just drinking it that can cause problems, here is a recent post of mine on the PBO forum:

When did you last disinfect your shower head?

As some of you may know, I've been in hospital with pneumonia. Soon after being released my CRP blood test had climbed back to 85: normal is under 10 (on admittance to hospital it was over 300, down to 25 when they released me).

Ten years ago my wife and I were both infected by Legionella in a spa hotel. Because they had overbooked, on the first night they put us in a rarely used room, at the time I was sure this is where the infection occurred, from the shower head.

After trying six other types, I am now on a more powerful antibiotic (Ciproxin) which is one that is used for Legionella (and Antrax). I seem to be getting better, it is possible that this was Legionella again.

I became unwell two weeks after arriving on my boat, the first visit for several months. We arrived late at night, I wanted a shower, and I had removed the light fitting on the previous trip. I didn't disinfect the shower head. I would normally do this by removing it, putting it in the basin with some citric acid to descale it, then rinse and soak in a bleach solution. When the calorifier has heated up, fit the shower head to the hose, hold the head under the bleach water (to avoid generating spray droplets), and turn the shower on at the maximum temperature.

This could all be a coincidence, but I urge you to read up on this subject, here is the HSE guideline.

Read more at Disinfecting Shower Heads

[Celestialsailor]

Originally Posted by Cottontop

From Ultraviolet.com:

"UV-C light is germicidal – i.e., it deactivates the DNA of bacteria, viruses and other pathogens and thus destroys their ability to multiply and cause disease. Specifically, UV-C light causes damage to the nucleic acid of microorganisms by forming covalent bonds between certain adjacent bases in the DNA. The formation of such bonds prevent the DNA from being unzipped for replication, and the organism is unable to reproduce. In fact, when the organism tries to replicate, it dies."

So, renders the bugs sterile, and kills them.

Why when I read this do I think of my step daughters latest fiance?

[sailorboy1]

Originally Posted by nigelmercier

It isn't just drinking it that can cause problems, here is a recent post of mine on the PBO forum:

When did you last disinfect your shower head?

Legionella loves plastic for some reason so ends up in shower heads. This of course goes air bound while taking a shower and you breathe it in. Boats running a low to no chlorine level in the water are perfect Legionella breeding grounds (boats in general are Legionella and other "bug" breeding grounds).

[PapaLulu]

Hoping to resurrect this thread as I wrestle with keeping our boat's potable fresh water system healthy. We have a 12-volt SLCE R/O watermaker that has a pumping problem. In the process of troubleshooting I began uncovered some challenges to keeping the system clean of bugs and stuff without ruining the R/O membrane. The watermaker has an automatic fresh water rinse which must be run following any watermaking to flush the system of raw water. The pump pulls fresh water from the water tank through a charcoal filter, decreasing the impact of any chlorination on the R/O membrane. Well, the automatic switch valve seems to be malfunctioning, preventing the pump from feeding the system any water, sea or fresh, and now I'm faced with trying to prime the system with the dock's fresh water to protect the R/O membrane while I troubleshoot the problem and order parts. Looks like I would need a charcoal filter between the hose and an adapter that fits into one of the freshwater watermaker hoses to avoid ruining the R/O membrane from chlorinated tap water.

This has led me to thinking about how I would periodically sterilize the water tanks and fresh water hoses (routed to shower heads and faucets, etc) without overwhelming the charcoal filters with too much chlorine. The only thing I can think of is to install a bypass of the watermaker system to periodically chlorinate the tanks and freshwater hoses, then flush the same with tap water before switching back to the regular watermaker-based supply.

Thoughts? There are almost certainly other threads that have touched on pieces of this so if you know of any please point me in the right direction. Still searching.