Delta UV systems for outdoor residential pools

The pool industry has a long history of taking products or services that have a legitimate 'niche' value, and then marketing them outside that niche:

=> TDS (total dissolved solids): TDS was a huge buzz in the pool biz for about a decade, and was routinely tested by pool dealers during the late 1990's and early 2000's. TDS can usefully indicate the 'age' of the water, but only in the context of a HISTORY of TDS measurements. Unfortunately, many pool owners were victimized by instructions to drain their pool or add this or that additive because their TDS was above 2500 or some other arbitrary value.

=> Stain control agents: Various organic acids and phosphate-based products have been, and are STILL, marketed to many pool owners without regard the presence of actual staining, or consideration of the complexity of properly using such products. For example, all the organic acids I'm aware of being used for stain control are COMPLETELY incompatible with chlorine.

Several of these products have real value, when applied correctly to pools where there is an actual need for their use. However, most pool owners sold these products do not need them.

=> Phosphate removers: Lowering phosphates to ppm levels below 250 ppb can inhibit algae. But on most pools, simply maintaining appropriate chlorine levels for the stabilizer level, is all that's needed. If there's no problem with algae, adding phosphate removers can't help anything. There are a few pools in which, for reasons unknown to me, mustard algae appears again and again, in spite of appropriate chlorine levels. A large local country club pool I service has this problem . . . and testing this fall has shown that lowering phosphate makes the algae in this pool much, much easier to control. But, of 40 large commercial pools I serviced for 3 or more years, only 2 had this problem . . . and only these 2 would have benefited substantially from the use of phosphate removal products.

Nevertheless, it has become nearly universal for pool dealers to sell phosphate removers to all pool owners. In a fine example of having the customer 'pee in his own soup', many dealers will simultaneously sell the poor pool victim a phosphate-containing stain control product!

OK. See the pattern?

The same thing is true of UV irradiation systems for pools.

Properly sized and fitted UV systems can offer real value to heavily used indoor pools, by making it possible to control otherwise recalcitrant chlorination by-products. Delta UV has a reasonable presentation on that -- very limited -- topic here: http://www.deltauv.com/-pdfs/WAHC%20...ber%202010.pdf

BUT . . . we've looked at this issue extensively, and we are not aware of ANY useful application for UV on outdoor pools, exposed to normal solar irradiation.

SO . . . if you have an indoor commercial pool with an air quality problem, a properly sized and fitted UV system can definitely help, though it will end up costing you more money for BOTH the UV system AND for increased chlorine usage.

Otherwise? As far as we can tell, a pool UV system is a total waste of money.