Study says many test kit results vary.

A recent study has concluded that "unacceptable differences" exist between field test kits used to measure pool water parameters.

The findings were released by researchers at California Polytechnic State University in San Luis Obispo.

The initial tests were performed by the actual test kit manufacturers, noted Dr. Damian Kachlakev, director of Cal Poly's National Pool Industry Research Center, where the study was conducted.

"We found unacceptable differences; some [kits] differed by more than 300 percent. What kind of water chemistry are we talking about," Kachlakev asked, when it comes to getting reliable results from these kits?

Cal Poly's NPIRC already has begun the second phase of the test kit study in which six universities around the nation will invite the same test kit manufacturers to participate.

"Tests will be done [at the six universities] and compared to the ATSM standards," Kachlakev explained. "We will have a team travel from college to college to act as witnesses."

He said that the colleges would buy the test kits in question from local pool retailers. This will help factor out variables such as shelf life and geographic location and how they affect the kits.

In addition, the NPIRC's recent study, which was sponsored by the National Plasterers Council, furthered the research on water chemistry and its impact on pool surfaces, particularly plaster.

"In this second study, all of the pools except two were balanced," Kachlakev noted. "The only thing that changed [from pool to pool] was the sanitizer used. In the first study, we just looked at aggressive water vs. balanced water."

The researchers said the tests confirmed that all cleaning solutions on the market today do not perform equally and that the addition of slow-releasing and more potent chemicals contributes to the etching deterioration problem.

The study involved seven common sanitizers. The results strongly suggested that pools sanitized with salt systems developed the highest level of etching, cracking and discoloration, while dichlor and calcium hypochlorite showed minimal deterioration.

The recent research also addressed startup procedures and their effects on plaster, as well as calcium chloride's impact on plaster when it's used as a catalyst.