Q. I have thought about using a no-chemical ozone or salt purifier kit for my swimming pool to save on chemicals and reduce eye irritation from chlorine. Are these kits effective and do they use much electricity?
A. People often are unsure about using ozone to purify swimming pool or spa water because of stories about harmful ozone smog in the air. Installing an ozone kit yourself, instead of using strong chlorine chemicals, is safe, natural and not related to ozone smog from cars.
Ozone gas is basically an active form of oxygen that reacts with bacteria, viruses, algae and other impurities in the water. At its low concentration levels in the water, it has no effect on your skin and eyes. Many municipal water purification plants use ozone to treat drinking water.
When the ozone gas dissolved in water comes in contact with impurities, it oxidizes them as chlorine chemicals do. It also causes particles, body and suntan oils, etc. to clump so the filter can remove them more effectively.
Most ozone purifiers for pools and spas use only about 0.5 amperes when they are running. This is about the same amount of electricity a 60-watt light bulb uses. Because the ozone generator unit runs only when the filter pump is operating, the total amount of electricity used is not great.
The ozone kit is installed in the existing pool or spa filtration plumbing. There are several basic designs of ozone generators, but they all inject the ozone gas into the pool water through a small tube. The concentration of ozone gas is strongest at the point of entry for effective purification.
An ozone system is not actually "no-chemicals," because you will still need to keep a very low residual level of chlorine in the pool water.
This is generally only about 20 percent as much chlorine as when no ozone is used.
The two basic types of ozone generators are ultraviolet (UV) and corona discharge (CD). UV systems use a fluorescent light to create ozone as the sun does above the earth. CD units use an electrical arc inside a generator to create ozone as lightning does (the fresh smell after a storm).
Salt-type purification kits are used to create a steady level of chlorine in the water. They use only a small amount of electricity to break down the salt in the water into basically the same chemicals as adding chemical chlorine does.
The required salt concentration in the water is only about one teaspoon per gallon, less than the salt in a human tear. Pool water purified by this method is comfortable to swim in because the salt also softens the water. Once the pool water is charged with salt, the concentration stays fairly constant.
Q. I have a metal roof on my house. It is secured to the sheathing with long screws with a rubber grommet under each one. The screws are coming loose. Should I just retighten them or will they loosen again?
A. You can retighten them, but they will probably work their way back out again even faster the second time. The thermal expansion of the roof causes enough movement to loosen them.
Try using the next larger size screw so it fits snugly in the existing hole. Once you install the screws, place a small piece of mesh over each screw and coat it with roofing cement or acrylic.
XWrite for Update Bulletin No. 759 which gives a buyer's guide of seven ozone and salt-type pool/spa purification system manufacturers (40 models) listing output levels, features, prices and installation instructions. Please send $3 and a business-size SASE to James Dulley, The Vindicator, 6906 Royalgreen Drive, Cincinnati, Ohio 45244. For an instant download, visit James Dulley online at www.dulley.com.