Cleaning The Pool: Newsletter Challenge (02/05/08)

Ozone! My hot tub uses it,

Tomas can utilize ultraviolet technology to kill bacteria while keeping his daughter rash free.

Look to municipal wastewater treatment systems, they have all been changing over to ozone often combined with UV. For the pool system and without the need of 99.999% purity as wasterwater treatment, a UV system would work. The water passes into the UV chamber where one or several UV bulbs irradiate the water. The UV has a peak at 254 nm, which happens to correspond well with the absorption of DNA. This results in the DNA being split and killing simple organisms such as bacteria and algae and even small parasites.

Tell Tomas to shop here: http://shop.solardirect.com/product_info.php?products_id=332

Now little Juanita can swim without those pesky chemicals.

Two choices: An ozone generator, or a high intensity UV source

I am thinking that a possible better solution is to regulate the chlorine with a simple feeder running off the filter pump and set the chlorine level at the same value that you get from a salt system.

The more I read about some of the alternates, chlorine doesn't seem too bad; if you control the concentration.

Some of the issues that I didn't consider is what is the environmental impact if you have to dump 20,000 gallons of pool water to repair the pool? That happened to the previous owner after a hurricane damaged the pool.

All of the alternate systems still require weekly shock treatments of chlorine (as recommended by the manufacture) anyway. Then there are long term maintenance costs. UV bulbs degenerate in intensity, other chemicals can stain or degenerate objects in the pool, blah, blah.

Does anyone know of a cheap and reliable electronic sensor for chlorine levels?

It would seem that if you could monitor the chlorine levels you could dynamically adjust the infusion of chlorine to keep the level consistent with the demand. A simple software program can easily manage that with a cheap PIC microcontroller.

Any ideas?

Could an Overhead tank and sprinkler sytem help.. Running/moving water when combined with adequate exposure to sunlight and air would prevent algae formation and also kill the parasites. Filters could clean the water when its moved from the swimming pool to the tank. A sensor could automate the pump function.. Evening it would move out the water from the pool.. Sunrise could activate the waters downward journery.. The tank could be fitted with solar panels to make the pump work..

STL hinted at using electricity. Tomas could build 2 large Tesla coils, one on either side of the pool. Then fire up the coils and let them run for a few minutes, and shut them down before anyone goes for a dip.

The coils could also be incoporated into a security system that will keep an interloper from taking an illicit midnight swim.

something like one of those backyard bug "zappers"?

Who said engineering couldn't be fun.

I assume that you are trying to create electrical discharges? That may do something in the air, but what effect do you expect in the water? Post #69 describes one view of what electrical storms can do to pool water (though it could be that the cause is not the electricity itself).

Frank N Stine

The coils could also be incoporated into a security system that will keep an interloper from taking an illicit midnight swim.

IMLUVINIT!

One other method is using biquanides-the same sanitizing agent used on contact lenses. The pool would have to be shocked (using bromamines-they break down fast in UV light) once every couple of weeks, and pH monitored. Because the biquanides dont break down microorganisms, the filters would have to be changed more often, and the scum line cleaned regularly, but precious little Juanita would get to swim safely without worrying about getting a tumor from 3D's tesla coil.

Chemical the pool like usual. Put the kid in a scuba diving Dry-suit. no skin/water contact, and acts as a flotation device to boot.

Based on the consensus here, the economic way would to use chlorine in large quantities and keep Juan (or should that be Alicia) away from the pool until the levels decay to suit her (which could be speeded up using a cascade or fountain).

In some areas of Europe, colloidal silver is used for disinfection of swimming pool water. Colloidal silver has been used as a disinfectant for > one century; however, the EPA has started action against its widespread use because it is too effective and a number of industries are using it without adequate controls.

Would ultraviolet light work

My question is where did the third character "John" appear from in the previous challenge question

Quote " Tom realizes that he could build a Galilean Telescope from the lens in the magnifying glass and a lens from Johns glasses (John is nearsighted). They could then use this telescope to do their research."

They don't tell us everything! They won't answer questions either. Then we all go nuts trying to figure these things out.

On a serious note, I think Alice had a sex change in the interim.

I can see where the UV system will not give a rash to Tomas, but does it solve Juanita's problem?

Tomas should consider an electronic water conditioner from Oxion Water Technologies (www.Oxionwater.com). It is very effective and affordable.

Swim in a European pool and you will notice there is no chlorine odor. Europeans have virtually standardized on ozone as a disinfectant, while Americans swim in a soup with more than 3 ppm chlorine. Ozone (O3) kills both algae and parasites, and any residual rapidly decomposes to harmless O2. Some low level of chlorine (about 0.5 ppm) is still recommended to ensure disinfection, however.

There is a line of pool chemicals marketed as 'SoftSwim', that I have used for ten years in my pool with excellent results. This system is peroxide based, but doesn't bleach hair or irritate skin (except in the concentrated form which is pretty nasty). In addition it doesn't require the constant monitoring with the ph test kit, and is therefore much less of a maintenance issue.

Caribbean Clear has worked well in my swimming pool for the past 20 years.

http://www.caribbeanclear.com/