Extraze Posted January 16, 2015 Report Share Posted January 16, 2015 Humor me here ... with the recent price drops in UV LED lights (260nm pure UV is still very expensive), but 280nm (medically rated) is starting to get decent at 100$ per high-powered LED, this starts making things interesting... so this got me thinking of installing LED lights on the inside of the cover (pointing towards the water), I don't really believe in UV lights "chambered" in the plumbing because there is not enough exposure to the bacteria due to the high flow of the pumps, but if there were a couple of UV lights shining down on the water when the lid was closed (specially when no pumps were running) a lot of bug-killing action would be going on! ... but then I got worried about how the spa's shell would react to a constant exposure to UV ? ... massive UV combined with Ozone would get people pretty close to a zero chemical solution ... unless I'm missing something. ? I think a fun discussion is in order Quote Link to comment Share on other sites More sharing options...
chem geek Posted January 16, 2015 Report Share Posted January 16, 2015 It's plausible but as you point out the high intensity UV that is strong enough to kill pathogens may be too harsh for the spa shell. You wouldn't have to have the UV intensity be anywhere near as high as the inline plumbed systems because you've got a lot more exposure time. You'd need enough ozone to have some residual going through the piping and it would need to be on enough to not have too much dead time. Otherwise, bacteria could grow in the piping where not exposed to UV. So that only leaves the disinfection during a soak since you won't have the UV nor the ozone on at that time. What you describe has no such disinfection during the soak so there is no prevention of person-to-person transmission of disease. If you soak alone or only with family members, then that risk is low. Quote Link to comment Share on other sites More sharing options...
Dr. Spa Posted January 16, 2015 Report Share Posted January 16, 2015 I think being in the cover would make it rather prone to damage. The cover would have to be wired to the spa, most covers have a limited lifespan (how do you transfer the UV system to a new cover?), taking the cover on and off would put physical stress on the system (even with a cover lifter). Also, most manufacturers tell you to always keep the cover on the spa and don't warrant damage to the surface caused by sun damage (UV damage). IF, there was a way to prevent damage to the shell of the spa, why not mount the UV lights in the side of the spa, like a typical light, and let it shine out into the water. A small circ pump could keep the water moving, so it gets exposed to the light (and would alleviate chem geeks valid concern about water in the plumbing). Quote Link to comment Share on other sites More sharing options...
chem geek Posted January 17, 2015 Report Share Posted January 17, 2015 Circulating the water through the UV is not enough. Bacteria tend to grow in biofilms so if any bacteria stick to the plumbing then the circulated water exposed to UV doesn't do anything to such biofilms. One has to have a bulk water disinfectant to kill pathogens stuck to plumbing surfaces. Ozone is possible for that because the ozonators in residential spas don't degas so there is some residual even if it is small (but it's enough to keep the plumbing clean). Circulation systems that occasionally run the jets and not just the regular circulation plumbing are a good idea to keep such spa jets plumbing free of biofilm. Quote Link to comment Share on other sites More sharing options...
Extraze Posted January 20, 2015 Author Report Share Posted January 20, 2015 I like the comments, I thought I would get more negative feedback to be honest ! I'm not 100% set on the lights being attached to the cover, it was my first thought, but these are still 2-3V LED's ... they could even be powered by batteries and they could float on water (but I'd rather have them hard-wired somehow... changing batteries every weeks isn't productive)... To be honest I haven't really thought of the placement a lot, but I know they cant just be sitting behind a transparent plastic cover like regular hot-tub lights because most plastics shield against UV... (because at first I actually thought about placing regular 50$ UV bulbs inside the hot-tub cabinet because the water hoses are transparent... but after some reading, I learned that even transparent plastic shields/absorbs 75-95% of UV)... not to mention the impact UV would have on every plastic component inside the cabinet... and even then, the flow is too high in the hoses so the effect of UV would only be when the pumps are off, and wouldn't affect a lot of water volume. so this means any decent UV system needs to be in direct contact with the water, and the flow needs to be reduced... a lot. I agree that the inner linings of the hot tub piping would not be exposed to the UV if the lights were on the cover or somewhere over the shell, which does indeed mean mold and bacteria could grow in the pipes. in my case I have a ozonator so that would help... but still, not 100% effective. im still not sure how the shell or other plastic parts would react as im not sure of what material they are all made of (or if they have any kind of UV protection imbedded in their plastics... im hoping the shells do because they can be exposed to long periods of sunshine... ) so with that in mind, im not going forward with this, but thought it would be a interesting idea. PS sorry but I have no idea why my text is all centered like that. Quote Link to comment Share on other sites More sharing options...
Dr. Spa Posted January 20, 2015 Report Share Posted January 20, 2015 "Im hoping the shells do because they can be exposed to long periods of sunshine"This is not correct. Most manufacturers will NOT cover damage caused by leaving the cover off for extended periods of time and damage to the shell caused by sunlight. Quote Link to comment Share on other sites More sharing options...
chem geek Posted January 20, 2015 Report Share Posted January 20, 2015 To prevent the automatic (and annoying) centering of post content, start your post with "[ l e f t ]" and end it with "[ / l e f t ]" where you remove the spaces and don't include the quotes. Unfortunately, every time you edit an existing post, you have to add these back in as they are removed. Quote Link to comment Share on other sites More sharing options...
Dr. Spa Posted January 20, 2015 Report Share Posted January 20, 2015 It works! Quote Link to comment Share on other sites More sharing options...
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