Overdosing PristineBlue.  These are the verbatim words of wisdom from Earth Science Labs, manufacturers of PristineBlue:

"What happens if I add too much PristineBlue?"
PristineBlue overdose can occur when PristineBlue is applied more than every two weeks or when the pool or spa volume is miscalculated. The signs of an overdose are often mistaken for other problems because of their similarity. The most common signs are high PristineBlue demand, cloudy or green tinted water, blue color in the filter, and consistently low PristineBlue level, even immediately after PristineBlue application.

When there is an overdose, the PristineBlue level will appear to be extremely low or even non-existent when tested with a PristineBlue test kit. For this reason, it is necessary to perform a “dilution test” if an overdose is suspected. This is done by mixing equal parts of pool or spa water and distilled water. Perform a normal test with this mixture and multiply the result times two. The result will be the actual PristineBlue level. For instance, if the test shows 0.7 ppm, the actual level is 1.4 ppm. Occasionally, an overdose is too high to be picked up with this test method. In that case, it is recommended that a water sample be sent to Earth Science Laboratories for more thorough testing. Call 800-257-9283 for instructions on sending a
water sample.

If dilution tests show the PristineBlue level is 1.0 ppm or above, it is recommended that PristineBlue not be added for another two weeks. Add 2 ounces of PristineClean per 10,000 gallons of water, filter 24 hours and backwash. If staining has occurred, refer to the PDF file on staining. Do not add any PristineBlue until the actual PristineBlue level has dropped below 0.9 ppm.

To prevent an overdose, do not add PristineBlue more than ever two weeks and double check pool or spa volume.

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