Chlorine Test

May 4, 2012
14
Hello Again,

I have been maintaining my new to me pool for a month or two now and I am very satisfied and comfortable with the pool thanks to the knowledge I have gained from TFP forum and I thank you all for that knowledge. But I digress.

I find that I only use the R-0870 DPD powder and the R-0871 drops to daily check my chlorine. I never use the the yellow capped R-0003 drops to check my chlorine. Is the DPD test more accurate than the R-0003 test? It certainly is easier for me to read the R-870/R-871 test.
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
42,989
Tucson, AZ
The OTO (yellow) test is fool proof on determining if there is 0 chlorine in the pool (clear) ... or a LOT of chlorine in the pool (yellow to orange to brown).

If your required FC levels are low enough, you can get by with the OTO test on a daily basis and use the FAS-DPD test less often to get specific numbers.

There is nothing wrong with always using the FAS-DPD test as it is much more accurate ... other than running out of reagents ;)
 

BoDarville

TFP Expert
LifeTime Supporter
Jun 5, 2012
3,844
DFW, Texas
russ.stevenson said:
I find that I only use the R-0870 DPD powder and the R-0871 drops to daily check my chlorine. I never use the the yellow capped R-0003 drops to check my chlorine. Is the DPD test more accurate than the R-0003 test? It certainly is easier for me to read the R-870/R-871 test.
The R-0870 powder combined with the R-0871 drops test FC. After recording the FC, the R-0003 is added to the R-0870/R-0871 solution to test for Combined Chloramines (CC). If the solution remains clear, you have no CC’s (this is good). If the solution turns pink, add R-0871 to the solution, counting and swirling between each drop. Once the solution returns clear, multiply the added drops times .5 again - this is your CC. The amount of CC is a determining factor in whether to shock.
 

frogabog

LifeTime Supporter
Jul 16, 2010
1,629
Portland, Oregon
You should be using the R-0003 to test for Total Chlorine, after you test for Free Chlorine with R-0870 and R-0871. After you are done testing by dropping R-0871 in and the water is clear again, put 5 drops of R-0003 in the same sample. If it turns pink, then you drop R-0871 in again drop by drop and count till it turns clear again.

Take the result of the R-0870 and R-0871 reading and add the drops you used in the second phase after using R-0003. This is your Total Chlorine (TC) result.

So, let's say you used 8 drops of R-0871 for a result of 4ppm Free Chlorine first, then added R-0003 and it turned pink. Let's say it took 2 drops to turn back to clear. Your results would be as follows.

FC = 4ppm
TC = 5ppm
CC = 1ppm

In this case, since CC is over .5ppm, you would need to begin the shocking process.

If the sample doesn't turn pink after adding R-0003, your CC result is 0ppm.

The reagent you would want to use for the OTO test is found in the blue box that is in your TF100, I think it's R-0450 or something (hard to read the label on the image). But it isn't R-0003, that won't work for the OTO.