Reverse Osmosis Water

[Bruce]

A reverse osmosis (RO) watermaker effectively filters bacteria out of the water, but viruses, being much smaller, are not filtered. Do viruses survive in the product water? If so, how much Clorox should one add to take care of viruses? Many cruisers do not worry about viruses in RO water -- is that safe? Thanks,

 

[Brian Pickton of BeneteauOwners.net]

Viruses

Feb.7,2001Dear Bruce,None of the long term cruisers and liveaboards I know add clorox (bleach ) to their tanks if they are using only water made by their water makers. If they use shore side water whether they add bleach is an issue of whether (a) the water has already been treated by the municipal supplier and (b) how they feel about having those foreign substances in their bodies. We have added bleach to rain water we have collected and to water we have gotten in third world countries, but only sporadically. So far it hasn't killed us. Until they find a cure for the common cold ( a virus), and bleach isn't it, I wouldn't worry about adding bleach to my osmotically produced water.Fair winds,Brian Pickton of BeneteauOwners.net,aboard The Legend, Rodney Bay St. Lucia

 

[Don Evans]

Further Filtration

I would check with the manufacturer of your RO to see if a 0.2 micron, final filter is part of or can be added to the unit. It is a very effective measure to ensure sterility, removing all virus. These can be purchased as a stand alone final filter, mounted after the RO. Not all virus are eliminated by contact with free chlorine, especially at the concentration needed to kill bacteria. Ozone is an effective bacti and viralcide, and I understand are being produced for the marine market.Don

 

[Tim Schaaf]

Beg to differ

Sorry, but RO does, in fact remove viruses. What it leaves in are things whose molecules are smaller than salt water. These include some surprising things. Some toxinc substances, for example. And about 60% of urine will pass through! But, not viruses. From a practical point of view, I would suggest that you not worry about drinking your RO water. It is probably the purest water you have ever drunk! Furthermore, chlorine destroys membranes. If you use the water you have put in your tank and chlorinated to back flush your RO system or otherwise clean it, you can say goodbye to this expensive item.

 

[john renfro]

kill it

hello bruce, it is three drops of bleach for each liter of water, or six drops if the water is cloudy, let the water sit for five minutes, then you can filter out any stuff you can see, if you want to.john

 

[Jim Ewing]

No treatment

I've got a PUR RO unit on the boat and it works great. I never add any treatment to the water or tank because chlorine is about the worst thing you can do to your water system. The water that comes through the PUR has lower dissolved solids than most tap water. The only issue I've noticed is that the water tastes "flat", it would probably help to put some in a bottle and shake it to add some gas back in.Jim"Prospect"