Tech tips - Tried & True methods for accurate Chlorine & pH readings
It is a well known fact that pool/spa water testing is one of the cornerstones of successful pool operations. But what if you get inconsistent and inaccurate readings?  What if they are so troublesome that your staff doesn’t trust them anymore?

You’re not alone. Many operators either: are given the wrong test kit, maintain poor testing discipline or procedures, or make some simple (and avoidable) mistakes involving pool water testing. Here’s how to correct.

Use the right kit:
According to DOH codes, commercial pool or spa must use a DPD-style test kit. This kit uses a chlorine test that renders a “red” result. This is in comparison with the residential “OTO” test kit that yields a “yellow” result. The DPD test yields a “free” chlorine reading, which is important in the operation of our demanding commercial pools. Then you add additional drops are added to the free chlorine reading to obtain the combined chlorine reading. For basic pool operations, CES recommends the Taylor DPD-based K2006, or commercial K2006C kit with larger reagent bottles.
The K2006 differs from the industry-standard K2005 in only one test -- the chlorine test. The rest of the tests are exactly the same. The chlorine testing protocol for the different kits are: 
K2005:  Add 5 drops of reagent #1 and 5 drops of reagent #2, to the water sample, creating a red-color, and compare that color against a silk-screened color chart. To determine the chloramine level, add 5 drops of #3 and observe the change in the color of the sample. This is now your total chlorine. To determine chloramines, subtract Total - Free = Chloramines.
K2006: Add two scoops of DPD powder to the 10 ml sample water, the sample turns red, then add drops of R0871 reagent, counting either 0.2 PPM per drop until the sample turns clear. (Example: 14 drops x 0.2 per drop= 2.8 PPM of chlorine). That is your free chlorine. To determine chloramines, add 5 drops of #3 reagent to the same sample water, if it turns pink or read, you have chloramine. Add drops of R0871, counting 0.2 PPM per drop until the sample turns clear. 

Maintain proper discipline:
The DOH code requires daily testing of chlorine residual. Some first-class pool operations in Florida test several times a day, as well they should. Readings should be logged on the DOH-required monthly log sheets, and should be kept as a permanent record by the organization. Lack of testing is the #1 culprit in large scale problems and the cause of many emergency service calls.

Avoid simple mistakes:
The K2006 kit is accurate, but only if it is used properly, and if major mistakes are avoided. 
Mistake #1:  Over-chlorination produces weird readings. Under high chlorine levels....the chlorine test bleaches ( to clear), the alkalinity test turns yellow-blue, instead of red-green and the pH test turns purple. Mistake #2:  The red and yellow colors on the pH test represent maximum color changes on the kit, and may not represent actual readings. If you get a bright red or yellow reading for pH, simple use reagent #5 and #6, following test kit instructions, and get the “correction” required to return the pH readings to desired levels.
Mistake #3: Incorrect pH readings. Under certain water conditions, the pH reagent on the K2005 and K2006 can give you incorrect readings. To correct, simple add 1 drop of R007 (thiosulphate) reagent to the sample water prior to conducting the test. This will neutralize the chlorine level and give you and accurate reading.
Mistake #4: Watch the old reagents. If reagent #2 gets a reddish tint, or reagent #3 get a cloudy appearance...they are bad, and can give you incorrect results. As a general rule, discard any reagents that are over one year old, and start new. It is cheap insurance against misleading readings that cause expensive problems.

Proper testing CAN BE the difference between a mediocre operation and a first-class program. You can follow these few simple steps and prevent some simple problems. Please contact your CES rep for more information on different testing programs.

Tuesday, January 16, 2007
For basic everyday test kit readings on smaller commercial pools, CES recommends the K2006 test kit. This kit uses the same pH, Alkalinity, Calcium Hardness, and Stabilizer tests as the K2005 kit. But, it has an accurate drop count chlorine test method, with 0.2 PPM increments & high upper limit.
To achieve more accurate & consistent pH readings,  ALWAYS add ONE drop of R007 - Thiosulphate to the pH sample water before conducting test.
Many CES customers have upgraded to the accuracy and repeatability of digital testing.