Cant get FC

Opened the pool several days ago & have been struggling to get a free chlorine reading even after pouring in significant amounts of bleach (25+gals). Last dose was 6 gal but it didn't get me a high free chlorinne reading. The pool water is crystal clear. Did backwash and pump pressure has been stable for last few days at ~9psi.

Current Details
27000 gal
FC 0.5
TC Very high - kit I have does not let me gage this well (waiting for Bens kit to arrive)
CC is therefore very high - but I cant break the chain! No chlorine smell to indicate this as being so high either
Ph 7.3-7.4
Total Alk 130
CYA - 35 I have raised this over the last several days but last night when it was in the 25-30 range I still didn't get a FC reading above 1 when I poured in 6 gal of bleach!

Gunite pool
Pool level was dropped by about 1/3 to 1/2 volume and re-filled before opening
I read that Total Combined Solids may be causing issues here but with the water change I am doubtful - dont have a measure on the TCS - may have to go the pool store for that

Any suggestions?

It seems your post has slipped through the cracks.

I think there may be an issue with your testing method or kit. Everything you've posted indicates to me your pool should have FC. Are you using strips? They will frequently bleach out at high levels of CL making you think you have nothing.

Before you do anything drastic ( I don't know what you'd do, all your other parameters are fine) dont add any more chlorine until you test by a second method. Take a sample to a pool store and be sure they use a drops based kit....I think you've got FC in there. Post your results from the pool store and we'll have more help available :)

PS - I doubt your CC is higher than 1, if that. Meaning you DO have FC.

thanks for the feedback - I am using a Taylor drop kit to test the chlorine levels not strips. I'll still take a sample to the store to see what they show - I'll get them to give me feedback on the the total combined solids too - I hope you're right and that I really do have FC - otherwise I'm stumped - will advise - thanks again.

Just don't buy anything they try to sell you, unless it's a toy! :)

Janet

Took a day or so - dropped the total alkalinity to around 90 and got the hardness to around 220. Ph dropped when I did the alkalinity so had to re-adjust that. Chlorine was pretty much depleated at this point so I shocked with 6 gal CHlorine - free chlorine registered at about 1ppm while the total went very high. Pool store had same readings? I'm stumped! Is it safe to swim with high CC?

How much after the adding of bleach are you retesting your chlorine levels? If you have high CC, the chlorine is going to quickly be consumed fighting whatever is in the water. I would not swim in a pool with high CC.

The TDS (Total Dissolved Solids) test is pretty useless. Pool stores seem to love it but it really has no bearing on your pool chemisty.

I checked the chlorine immediately after shocking and then half hour and hour intervals. Same result. The pool water is crystal clear and the pool pump is not building pressure due to contaminants. Not sure what the chlorine is combining with!

Which taylor kit are you using? (K-2005, k-2006, or a different one?)

cant find kit number - bottles are labeled as DPD reagent R-0001, R-0002 & R-0003

Quote:

---

Originally Posted by t_bodman

cant find kit number - bottles are labeled as DPD reagent R-0001, R-0002 & R-0003

---

Kit number doesn't matter, the reagents have identified it ....It is a DPD test and not an FAS-DPD test. It can bleach out and show no FC when the chlorine levels are above abot 10 or 15 ppm. You need to dilute the sample and test to get an accurate reading.