High Chlorine readings - how do they impact other readings

[Charlie]

I have a Taylor test kit that I've been using for years, and usually get a new kit every 2 years. My kit is stored in my garage and does not see daylight until I use it. Recently, I emptied 75% of the water and replaced with fresh water that comes into my house. That was a month ago. The reason was my calcium level was ~500, and it was evident on the tile with a visible white line.

In testing my water yesterday, it showed:
Chlorine: 5ppm
PH: 7.2
Alkalinity: 90
Calcium Hardness: 260
Cyanuric Acid: 65

Which I think are good numbers. For the heck of it, I took a water sample down to Leslie's pool store to double check the calcium hardness since I just replaced 75% of the water in the pool. The store values were reported at 175. My fill water is 160. I told him that his reported values must be incorrect since they differ than my readings. He said they are different because my high chlorine level, which begs me to ask the question if a chlorine level of 5ppm would do this (personally I don't think it would). Thoughts?

Second, what are your thoughts on a magnetic water conditioner? According to what I've read, its suppose to:

Magnetizer helps reduce sanitizing chemical usage by 30% to 50%. By helping to stabilize the pH and eliminating many pH chemicals, chemical costs are reduced. The Magnetizer helps to eliminate algae, helps keep the water cleaner and improves the clarity of your pool or spa.

For me, I'm looking at this device to help control scaling on the tile (water line).

[chem geek]

Mmmmm. Let's see. 25% * 500 + 75% * 160 = 245 which is pretty close to your measured 260. I'd say your measurement is the correct one.

High chlorine levels should not affect the CH test. Chlorine levels above 10 ppm affect the pH test, usually making it read too high. High chlorine levels can also make the TA test go from blue to yellow instead of the normal green to red.

Richard

[waterbear]

Pool magnets are nothing but snake oil! They have been around for years and all they do is lighten you wallet! If you decide to buy one please contact me about a bridge in Brooklyn I would like to sell you!

The only other test that high chlorine levels could affect is the chlorine test IF you are using DPD (not FAS-DPD titrations or OTO) since DPD starts to beach out at about 10 ppm and will read low or no chlorine slightly above this level.

[CarlD]

Hey! That's MY bridge! I got a receipt!

I would raise FC a little--with CYA=65, you are at the very low end of "safe" with FC=5 The recommended range for CYA=60 to 90 is FC of 5 to 10 ppm.

[waterbear]

Hey! That's MY bridge! I got a receipt!

Sorry Carl, I forgot I sold it to you last year! There is still that real estate in the Everglades available.

[CarlD]

Sorry Carl, I forgot I sold it to you last year! There is still that real estate in the Everglades available.

I gotta get in on that! I think I'll see if I can still get a no-principle ARM to pay for it.

"Hey! This is MY swamp!" --Shrek

[giroup01]

How about interfering with the CYA reading?

In the spring 1996 issue of the JSPSI Journal, Wojtowicz discusses the interferences in CYA testing. He suggests that if stabilized chlorine is used then "ideally the available chlorine should be reduced with thiosulfate prior to precipitation since some of the CYA is in the form of chloroisocyanurate" as the method has been calibrated for unchlorinated CYA solutions.

Prior to the chlorine reduction he suggests a 10 ppm chlorination (or using Oxone) to oxidize any oxidable materials that may interfere with the test - compounds such as uric acid may precipitate with melamine, for example.

But all this may be splitting hairs given the intrinsic precision (or lack thereof) of the CYA test.

[waterbear]

Under laboratory conditions these interferences might be significant but not to a home tester with a home test kit.

[Charlie]

LOL - you guys are talking over my head, but from reading all this, it sounds like I have nothing to worry about as long as the FC is below 10 when testing water?

Also, I purchased a new test kit from Leslie's pool store. It looks just like the Taylor 2005 test kit, but instead of a powder, it has R-0001 DPD Reagent #1 and R-0002 DPD Reagent #2. I add 5 drops of each. Just curious if one is better than the other. Seems like the powder would degrade faster than the drops.

The test kits says, "manufactured for Leslie's swimming pool supplies by Taylor Technologies, Inc. The number on the kit is 81-330. Its identical to my old 2005 except for the power that tested chlorine.

Leslie's numbers:
FC = 6 (I estimated it to be between 5 and 6)
pH = 7.7 (I measured 7.2)
TA = 100 (I measured 90)
CH = 175 (I measured 260 - note he used less water sample and less drops)
CYA = 80 (I measured ~65 - a test I hate because its so inaccurate due to looking at the black dot when it disappears).
Phosphates = 250 (I did not have any way to check this)
Salt = 2800 (same value I recorded)

The Phosphate issue for the last couple of years, I've been adding Phos Free to reduce it, but it increased my CH to the point where I had no choice but to drain ~ 75% of the water and replace it with fresh water. I don't plan to use that stuff anymore going forward for 2009.

So it sounds like you guys are saying to keep my FC around 5 to 6, even though the test kit recommends 3-4?

[waterbear]

LOL - you guys are talking over my head, but from reading all this, it sounds like I have nothing to worry about as long as the FC is below 10 when testing water?
basically, yes.

Also, I purchased a new test kit from Leslie's pool store. It looks just like the Taylor 2005 test kit, but instead of a powder, it has R-0001 DPD Reagent #1 and R-0002 DPD Reagent #2. I add 5 drops of each. Just curious if one is better than the other. Seems like the powder would degrade faster than the drops.

the kit you got is a rebranded Taylor K-2005 which uses the colormetric (color matching) DPD test procedure. This is not as good as the K-2006 which uses the FAS-DPD titration. The titration test does not suffer the bleachout problem when testing high (shock) levels of chlorine and it has a much wider range (can test up to 50 ppm chlorine) and a much greater precision (down to .2 ppm).
The downside is that it is slightly more expensive per test and takes longer to complete the tests but these are small tradeoffs, IMHO, for the increased range and precision and the lack of bleachout!

The test kits says, "manufactured for Leslie's swimming pool supplies by Taylor Technologies, Inc. The number on the kit is 81-330. Its identical to my old 2005 except for the power that tested chlorine.

SO given all the above I would have to say the K-2006 (with the titration test and DPD powder) is a better test kit than the K-2005 (with the color comparator and the liquid DPD reagents)

Leslie's numbers:
FC = 6 (I estimated it to be between 5 and 6)
pH = 7.7 (I measured 7.2)
TA = 100 (I measured 90)
CH = 175 (I measured 260 - note he used less water sample and less drops)
CYA = 80 (I measured ~65 - a test I hate because its so inaccurate due to looking at the black dot when it disappears).
Phosphates = 250 (I did not have any way to check this)
Salt = 2800 (same value I recorded)

The Phosphate issue for the last couple of years, I've been adding Phos Free to reduce it, but it increased my CH to the point where I had no choice but to drain ~ 75% of the water and replace it with fresh water. I don't plan to use that stuff anymore going forward for 2009.
PhosFree is lanthanum chloride. It really had no effect on CH. BTW, phosphate removers are basically a scam to make pool stores money!!!! They are totally unneeded over 99% of the time!

So it sounds like you guys are saying to keep my FC around 5 to 6, even though the test kit recommends 3-4?

Reread the stickies at the head of each forum section, this one in particular:
http://www.poolforum.com/pf2/showthread.php?t=365

All the basics of good pool maintenance are basically contained in the stickies!