Pretend we're at the AQUA Show in Las Vegas, where, you know, wagering is allowed. You get a call on your cell phone. It's one of your customers, and she's got a big pool problem. What's your bet. Stains. A 20,000-gallon fiberglass bowl of orangeade. Backyard pool now a backyard pond?

You might make a little money here, because each dealership has its characteristic pool problems. That's because although algae is basically algae, and dissolved iron is iron, rural Alabama is definitely not suburban Chicago. The climate is different, the source water is different, even the pool culture is different.

So we asked dealers from disparate regions of the United States to give us a rundown of the kinds of pool puzzles they're likely to see in an average summer. We then posed their problems to three experts in the field.

Do the dramatic variances in climate, culture and clientele induce particular pool problems? And what should pool care professionals bear in mind when treating them? Let's see . . .

Classic Pool and Spa, Canby, Ore.

Pool Care Professional: Judy Pipkin

Problem: Sudden Spring

"In our pool season, you've got 80 to 85 degree days, and then for a week or more you just get rain and 60 to 65 degree days. And when the weather turns cold and rainy, people have a tendency to ignore their pools. They just don't have any interest in going out there.

"Of course, they should be treating their pools exactly the same way they do when it's 85 and they're swimming in them. But they don't.

"And when they ignore their pools, they turn their pumps off, they stop checking their chlorine, and you know what happens . . . they get a nice fresh bloom of algae."

PUETZ: "If someone isn't watching the pool, you want something in the pool that overcomes that failure to watch." Instead of pouring in a large amount of algaecide after the greens are in the soup, Puetz recommends small doses "as a preventative maintenance tool, that is, once a week or once every other week. It will protect the pool even when other things (such as the sanitizer) are being overlooked or avoided."

ROUSE: "It is important for the customers to be on a maintenance program like the once-a-week three-step program. If you provide defined guidelines that are easy to follow on a weekly or biweekly basis, the customer will be more likely to pay more attention to their pool."

Problem: Outside Interference

"I'm out here in a farming community, outside of Portland, where there are a lot of fertilizers and chemicals borne by the wind. It can cause problems in the pool, and you can really get quite a pH adjustment from that, depending on what they're using."

ROUSE: "Fertilizer contains nitrogenous compounds which will cause a chlorine demand if they find their way into a swimming pool."

PUETZ: "And if the customer starts tossing in TriChlor in response, that chlorine addition will have a dramatic effect on pool balance. It will have a tendency to erode total alkalinity and lower pH.

"Fertilizers by their very nature are going to fertilize all living things — all green things. If fertilizers are being blown into the pool, you have an increased risk of algae growth, and that happens for two reasons: One, the algae can feed on it, or two, its nitrogen components react with chlorine, creating combined chlorine, therefore interfering with the sanitizer's performance.

"All the more reason to use a backup dose of algaecide as a preventative."

Problem: Black Adder Strikes Again

"We get some pretty bad algae problems. If it's black algae on a gunite pool, it really digs in with its little roots."

DONALDSON: "There is a magic wand that gets rid of black algae. Unfortunately, it's a stainless-steel brush and a lot of elbow work. We like to use TriChlor granular on those spots, let it settle on there overnight, and brush it in the morning. You may have to do that for two or three days.

"Black algae has roots that go down deep, sometimes all the way through the shotcrete. If you're refinishing a pool, you must make sure that stuff is dead, because if you put a new exposed-aggregate finish over a pool that has black algae in the walls, you're probably going to get it growing right through the aggregate."

ROUSE: "Black algae is especially hard to kill if the plaster is old and extremely pitted. The best way to prevent black algae is by maintaining an ideal sanitizer level, using a maintenance dose of back up or another quaternary ammonium algaecide and brushing the surface as often as possible."

Problem: Hi-C

"Some of our pools have high calcium content . . . well, you don't want to keep throwing in calcium hypochlorite."

ROUSE: "Some parts of the country have source water calcium levels as high as 300 ppm, so if you do have high calcium hardness levels in your source water, you're right, calcium hypochlorite is not a good option. Since that has calcium in it, by adding it you would continue to build the calcium level even higher, and if it gets too high you get scaling on the pool and cloudy water.

"If a swimming pool has a high calcium hardness level, I would suggest using a lithium hypochlorite product. And scale inhibitor will be needed to prevent scale formation if the calcium hardness level is high."

AQUA-TEKnology Pool & Spa, Rockville, Ind.

Pool Care Professional: Lori Burch

Problem: Liquid Metal

"We live in a rural area, and we have a lot of wells. Several wells have metal problems, mostly copper and iron, and a little manganese, so we have to be concerned with that, especially with the chlorine pools. Because you don't want anybody with metals in their water to shock their pool, as they're liable to stain their liner."

PUETZ: "Knowing you are in a metals area, it will be much easier, and much more reliable over the long term, to use a sequestering agent on a regular basis as recommended by the manufacturer to prevent staining. Preventing stains is a much, much easier thing to do than removing them once they occur.

"If you're about to fill the pool, a water analysis is critical, as you always want to know exactly what's going into it. When you do start filling the pool, the most important thing to do is to add a full dose of sequestering agent.

"A sequestering agent is low-cost insurance against an expensive stain which will be difficult to treat. My recommendation is that you start filling the pool, and when you have some water collected in the deep end, add a full dose of sequestering agent, even though you only have a few gallons of water in the pool at the time. Now, through the whole process that sequestering agent is present and tying up metals in the pool.

"Once done, wait a minimum of 24 hours. That will allow for a complete complex to take place, no matter whose sequestering agent you are using. And if you are in a high-metal-content situation, don't worry about using extra sequestering agent because it will do no harm. And don't hesitate to wait a few extra days before you shock the pool.

"During this waiting period, you want to establish a chlorine residual because you don't want to give algae a chance to grow. You may want to add a non-metallic algaecide to the water to prevent algae growth while you let the sequestering agent do its work on the metals. It keeps the pool safe from algae for a few days.

"And then, rather than just nuking the pool with chlorine shock, raise the residual slowly for a couple of days. Start with a 1 ppm residual, and then once you feel you have the situation well in hand, go ahead and shock the pool.

"You don't have to blast it. Sneak up on it a little bit.

"I know, there are builders who don't feel they have time to do all of that, but on the other hand, it will take some time to sit down with the customer and explain why the pool is stained."

Problem: Pink Stinks

"We get pink slime in some of our biguanide pools."

ROUSE: "In biguanide systems, you have a bactericide or sanitizer (biguanide) and the hydrogen peroxide is your oxidizer. If you develop slime or mold, you'll see added demand on hydrogen peroxide, so you'll have to add it more frequently.

"Pink slime and water mold may build up in the circulation system causing cloudy water and excessive use of hydrogen peroxide. Chlorine dioxide is the best way to prevent and kill slime and mold. If that's not available try a closed loop treatment."

Above-Ground Pool & Spa Company, San Antonio, Texas

Pool Care Professional: Sharon Stone

Problem: We Live In An Outdoor Sauna

Extremely hot weather, high bather loads and variable rainfall (sometimes very heavy). "Our season extends to at least the end of September, middle of October. It gets up to 100 degrees, and it feels like someone has thrown a wet, hot blanket over you when you go outside. And they're out there using the pool every day."

PUETZ: "You have two things that are working against you in hot weather. Hot weather brings more people to the pool and there's more chlorine demand on the pool. Rainfall, too, puts a demand on the pool in two ways. One is by diluting the water with untreated water, and the other is that heavy thunderstorms bring a lot of nitrogen into the pool.

"Nitrogen neutralizes chlorine, turns it into combined chlorine. In addition, it fertilizes your algae. It does the same with your lawn. That's why a lawn will turn green after a thunderstorm. It's the nitrogen fertilizer in the rainwater.

"People may call up after a thunderstorm and say, 'I've got this algo-bloom in my pool.' Well, the chlorinator may have failed, and the demand may have gone way up, but if you're using a small amount of algaecide every week, that algo-bloom probably won't happen. The service guy won't have to go back to the pool, the pool will remain in good shape, and the owner will be happy.

"People keep buying algaecide to kill algae, and I understand that, but if you just use a small amount on a regular basis you can prevent the problem. Let the chlorine do its work at killing bacteria, and let the algaecide keep the algae out of the pool."

DONALDSON: "When you get a big rain, it can overfill the pool, and a lot of people won't drain down the pool. Then your skimmers don't work properly. Now anything that falls into the pool, instead of getting skimmed out, falls to the bottom, and you end up with a lot of organics in the pool."

"The second thing is that rain tends to be acidic. It lowers the pH in the pool. Here in Florida we see high-acid-content rain with organics in it. There's nothing prettier than a pool with a pH of 6.0. It's beautiful water. Of course, it will take your skin and eyelashes off, and destroy the surface of your pool, but man, it looks good.

"The thing I can't stress enough is maintaining the total alkalinity — which is a measure of the water's ability to resist a change in pH. If you have a proper total alkalinity, you will be better able to withstand pH changes due to rain and so forth.

"But if your total alkalinity is not in the proper range, when you look at your pH, you don't really know what you've got there, because it will bounce around and be something different soon.

"I always recommend that people test every couple of weeks for total alkalinity, adjust it, and then test for everything else. Because then you can get proper readings."

Problem: Colonel Mustard In The Deep End

"Tenacious mustard algae and green algae are easier prevented than removed."

DONALDSON: "Sodium tetraborate pentahydrate — basically Twenty Mule Team Borax — is a remarkable product in my opinion. It's one specialty chemical that I've found to be very effective. It's sold as a registered algaecide, and it does a really good job of keeping the algae out and reducing the amount of chlorine consumed, but it also works like a pH buffer. It raises the pH when you put it in, but once you set the pH of the pool, it really stays there."

ROUSE: "Mustard algae can be difficult to treat. Use a copper-based algaecide, preferably one that is chelated to prevent staining — like Banish — to treat the pool. Be sure to put all equipment and toys into the pool during treatment to prevent the reintroduction of algae. As always, it's best to prevent the algae bloom in the first place."

PUETZ: "With any algae, but particularly with mustard algae, kill it with mustard algaecide, but make sure you clean the filter, because mustard algae can contaminate and reside in that filter.

"Some people will tell you, 'I keep getting it out of the pool, and it keeps coming back.' Well, the source of that returning algae is the filter."

Our panel of experts

Tom Donaldson, executive director, Aquatic Training Institute, Gainsville, Fla.

John Puetz, vice president of research and development, Advantis Technologies, Alpharetta, Ga.

David Rouse, manager of technical services, BioGuard, Lawrenceville, Ga.

Scott Webb is Executive Editor of AQUA Magazine.