never seen this happen before???????

[fast1971chevelle]

I went over to my brother in laws today to test his water with my trusty test kit in hand his pool had some dirt run in it from the heavy rains the other night, he uses 3 inch pucks but he shocked it with 8 gallons of liquid shock 2 nights ago per pool store it is a vinyl lined 20x40 inground and new liner installed 4 years ago and has been using pucks ever since, and I was testing his t/a and the sample turned a light blue when I added reagent r-0008 and then I started adding reagent r-0009 drop by drop swirling the whole time at one point it started to turn red and then it went back to blue and then to yellow and stayed yellow for 25 drops and then I ran out of r-0009......why yellow?? bleach out?

fc 38.5
cc 0
ph 7.6
t/a ?????
ch 250
cya 140

 

[jblizzle]

extended-test-kit-directions-t25081.html#p206395

It goes from blue to yellow when the FC is high. You may want to try adding extra R-0007 as suggested in the link above.

 

[fast1971chevelle]

so it is bleaching it out?
that's what I thought anyways.....lol
thank you jblizzle

 

[chem geek]

so it is bleaching it out?

Sort of -- it's half-bleached. The Total Alkalinity (TA) indicator dye in R-0008 is a combination of Bromocresol green and Methyl red dyes. At high pH above 4.5 the Bromocresol green is blue while the Methyl red is yellow so the combination looks green. At low pH below 4.5 the Bromocresol green is yellow and the Methyl red is red so the combination looks red (or red-orange if you keep adding extra acid drops in the test). High levels of chlorine will oxidize the Methyl red so that it is no longer colored so all you are left with is the Bromocresol green that goes from blue to yellow as you go from pH above 4.5 to below 4.5.