THE VIRGINIAN-PILOT
Copyright (c) 1994, Landmark Communications, Inc.
DATE: Sunday, July 31, 1994 TAG: 9407270037
SECTION: HOME PAGE: G1 EDITION: FINAL
SOURCE: BY KEITH MONROE, STAFF WRITER
LENGTH: Medium: 82 lines
THE HOTTER the weather gets, the more inviting a swimming pool becomes. Unfortunately, it's not just the humans who feel the attraction. The algae agree.
``The higher the temperature of pool water, the more likely algae is to grow,'' says Brad Hughes of AAA Pool Service Inc. in Virginia Beach. His company manages and maintains large community pools and must keep them free of algae.
Recent high temperatures and frequent rains have made that a challenge in and around Hampton Roads.
Hughes says algae comes in two forms: floral, which are one-celled plant organisms, and black, tiny crustaceans living in conjunction with floral algae.
The floral variety first turn a pool cloudy, then a scummy opaque green. Black algae can cling tenaciously to a pool's walls.
In addition to heat, a water pH that's too acid or too alkaline can encourage algae to flourish. A pool's pH can be altered by swimmers.
And because algae can be airborne, the same summer rainstorms that force people out of pools can drive algae into them.
``An oxidizer and a sanitizer is what combats algae,'' Hughes says. And that generally means chlorine. ``It kills algae and reduces the size of debris so the pool filter can remove it from the system.''
But the key is to avoid algae in the first place, Hughes says. Maintain free available chlorine at 1.5 to 2 parts per million and keep pH between 7.2 and 7.6. ``If the pH is higher or lower than that, it greatly decreases the efficiency of chlorine.''
Operators of big pools, like AAA, can monitor pool chemistry constantly. In fact, Hughes says, automatic controllers are becoming popular. But the price is prohibitive for most home pools.
Sabina McPherson of Aqua Leisure, a pool and spa retailer with stores in Virginia Beach and Portsmouth, says individuals can avoid algae problems simply enough. ``Take care of your pool,'' she says.
Check often to make sure chemicals are in balance, McPherson says. ``Shocking'' a pool once a week is also a good idea.
``That means superchlorinating it to a chlorine level of 6 to 10 parts per million, generally Sunday night after the week's heaviest use,'' McPherson says. ``Shocking burns up dead and live debris. Then follow up the next day with an algicide.''
Once algae gets a toehold, it grows. ``If it reaches the greenish stage, double shocking may be required,'' McPherson says. ``A chemical called a floc may also be needed to drop dead matter to the pool floor. Then vacuuming on waste will be needed to remove it.''
Black algae is even more difficult to remove because it can't be seen until it is many layers thick. Chlorine at shock levels for several weeks and daily scrubbing may be required.
To keep algae at bay, McPherson also recommends an extra shot of chlorine or algicide after a heavy rain. ``A filter system should be run a minimum of 8 to 12 hours a day - otherwise all the pool's water isn't being cleaned,'' she says.
If daily maintenance doses of chlorine aren't possible, during a vacation for instance, an algicide is essential. ``Sun removes chlorine, so leaving a pool for a week with only chlorine means you can return to a mess,'' McPherson says.
But ``any pool with a decent filtration system can be cleaned up without draining the entire pool,'' she notes.
There is one exception to that rule, though. It concerns the use of too much of the stabilizer cyanuric acid. It's used to help keep chlorine in the pool, and is an ingredient in some chlorine tablets. But too much of it - more than 100 parts per million - can necessitate partially draining the pool to restore a balance to the chemistry. The problem can arise because, unlike chlorine, cyanuric acid does not naturally dissipate, but continues to build up.
If a problem does develop, experts say, it's almost certainly because routine maintenance has been neglected and the pool chemistry has been allowed to get out of balance.
With water restrictions in effect in some area cities, home-pool owners are wise to control the water before growth begins.
If you're uncertain about maintenance, consult a pool professional. Most can diagnose a problem from a sample of pool water and recommend the right medicine - generally without a house call. by CNB