It looks clean, it looks sparkling, a backyard pool is supposed to be the place to cool off on a summer day.

But how do you know it's safe for your kids to jump in?

Anyone who owns a pool knows the drill you've got to add chemicals, use test strips, fight the rain, the heat, the swimmers, all to keep the pool clean and healthy.

Theresa Enos, pool owner"My husband tests the pool every few days."

Having the correct chemicals and all the readings, that's important to keep everybody safe.

But our investigation found how much treatment your water needs and how much it'll cost all depends on who's testing it. And they could be wrong.

This Tewksbury family let us experiment with their pool, after several days of rain, they knew their pool would need tweaking.

Using brand new collection bottles we took samples of the water, all at the same time, all in the same part of the pool.

A producer and photographer headed out, undercover, to pool supply stores

I took samples to this state certified lab.

The lab does not sell pool supplies, and charges 40 bucks to test the water. It uses nationally approved protocols and calibrated machines and has to pass annual lab inspections. Most pool supply stores do not.

 Jay Chrystal, Chem Serve Lab"If they're not certified, there's no third party making sure that they're doing things correct."

We wanted tests for bromine, calcium hardness, alkalinity and pH if they're out of balance, you could get rashes, red eyes, and other health problems. We were were told: that'll take two days.

At the same time, the undercover team took its water samples to four different pool stores, not state certified labs. Store shelves were stocked with pool chemicals, but tests were free.

Each place did the same pool tests: but one used test strips and the others used drops. At each place we got our results instantly.

But at each place, the results were different. Which one was right?

Not one. When the lab results arrived, they showed every pool company had them wrong. And some were way off!

Even pool professionals said: that's unacceptable.

Geoff Brown, The Association of Pool & Spa Professionals"I wouldn't expect that kind of disparity."

And since the test results are incorrect, the amount of chemicals you'll be told to buy to make your pool safe will also be wrong.

Geoff Brown, The Association of Pool & Spa Professionals"Either they walk out with not having spent enough money or perhaps having spent too much."

And look one company told us $29.99 and we were in the clear.

Another said $70. Another: $104, and another $122 ! The same pool!

Jay Chrystal, Chem Serve Lab"You can put our family and people at risk if you're over treating or under treating."

So add another step to your pool ritual–before you jump into an expensive purchase–make sure you know what's in the water.

Pool experts suggest, just like going to the doctor, get a second and third opinion on your pool test results. That'll lead you to a store you can trust.(Copyright (c) 2008 Sunbeam Television Corp. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)


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