Thread: Water quality
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Old 03-29-2014, 01:30 AM   #38
jungpeter
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City: Everett
Country: US
Vessel Name: LIBERTY
Vessel Model: TOLLY 48
Join Date: Mar 2013
Posts: 214
To Larry M: To my knowledge, UV sterilizers work literally at the speed of light-no warm up required. And, the longer the water is irradiated, the more likely that none of the "bugs" survive their swim through your water system and into your body. So sizing the sterilizer to your flow rate is important. And yes, I do subscribe to professional medical opinion that bacteria and viruses do, in fact, live in your fresh water system, no matter the source of the water that was placed into the storage tank.

Again, to the best of my understanding, a UV sterilizer is most properly used (in the context of our recreational vessels) immediately downstream of the water storage tank outlet, and therefore prior to any end-use of the water. One could argue that, given the lengthy fresh water piping runs on a typical boat, a UV sterilizer should more properly be employed immediately UPSTREAM of each outlet intended for human consumption. But that's not really practical, so a single UV sterilizer plumbed into the fresh water supply immediately downstream from the storage tank was my choice for my installation.

Mine runs on 40W of 110VAC. The sterilizer was sized to be somewhat larger than the maximum output of my fresh water pump, which is ~5gpm. I used a sterilizer rated for 12gpm flow. As the sterilization chamber (about 2" dia x 36" long) gets rather hot (~120 deg F) without water circulating through the chamber, I do not leave it on 24/7. Rather, I plumbed a flow sensor downstream of the demand water pump that activates a 12V/110V relay to provide power to the sterilizer whenever water flowed through the water pump, and 110VAC was available. In the instructions I received from the manufacturer of my sterilizer, there was no indication that it would be harmed by intermittent operation. It's really only a fluorescent light bulb, but emitting in the UV band instead of the visible light spectrum. How long will the bulb last? Beats me-they're cheap and easy to replace should the bulb fail.

Mine was supplied by the Clean Water Store. Residential Well Water Treatment, Iron Filters, Acid Neutralizers, Chlorinators

All-up cost was ~$300, including sterilizer, flow sensor, water hose, relay, wiring, etc.

Hope this helps.

Pete
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