UV-C vs Ionizer - Need opinions

[dashmer]

Hello,

I am soon to receive a new Beachcomber hot tub and I am interested in having the dealer install a supplemental sanitation system to go with my plan to use chlorine.  Beachcomber tubs are fitted for a UV-C system they sell that is plumbed inline with the circulation pump.

The dealer also suggested an ionizer as an alternative to the UV-C and it is a little less money.  The unit in question is:

https://www.clearblueionizer.com/en/hot-tub-spa-ionizer/

I am interested in hearing opinions on these two systems and which is best way to go.

Thanks

[RDspaguy]

Having never used a uv system I can't say how effective they are at eliminating chloramines and chlorine from the system, but assume they would be similar to an ozone generator.

A silver ion purifier that is "built in" is usually more expensive than the type that install in the filter. I am not familiar with that brand.

I use both ozone for chlorine and chloramine reduction and a silver ion purifier for a secondary sanitizer against chlorine resistant pathogens and to allow the low chlorine environment created by ozone.

[waterbear]

I would recommend against the ionizer. They call it minerals but in reality it's putting metals into your water. Clearblue uses silver, copper, and zinc in an electronic ionizer system. It is not a passive system like Nature 2 or FROG (which I also am not a fan of). These are basically algaecides that have some activity against bacteria but very slow kill times and no effect against viruses, which is why they must be used in conjunction with chlorine. Copper is particularly problematic since it can and does  stain spa surfaces and turns hair green (green hair, often wrongly attributed to chlorine is actually cause by copper either from copper ionizers or copper based algaecides and the staining is more likely at the high water temperatures in a spa.

UV-C (using a 254 nm germicidal lamp that filters out the ozone producing wavelengths) will sanitize the water in the reaction chamber but there is no residual effect in the water and the amount of water sanitized at any given time is extremely small so a primary residual sanitizer is still needed at normal, not reduced, levels. The upside to UVC germicidal with chlorine is that it will help destroy combined chlorine if the lamp is also passing UV in the 250 to 385 nm range(some do, some don't-Medium Pressure UVC bulbs work but tend to be expen$ive), which can be a problem in chlorine spas because of the high bather to water ratio. UVC germicidal  will not generate ozone, btw. (UV ozone generation is the most common type of ozone generation in hot tubs because of the lower cost when compared to corona discharge ozone generators but it uses a different UV wavelength, 185 nm UV lamp )

In short, both are added expenses with dubious benefits. If it were me I would forgo both and maybe consider adding ozone instead if you want a supplemental system.

[dashmer]

Thanks very much for the advice.  I now have some information to think about.