chlorine levels suddenly not holding

[vagrowr]

I SLAMmed my pool for a week and got it clear about 10 days ago. Since then, I have been maintaining between 4 and 7 ppm FC, generally needing to add 1 or 2 gallons per day of bleach (12.5%), and the water has stayed nice and clear. Yesterday morning the FC was at 3, a couple kids swam a little bit, and it was .5 last night. I added 2 gallons of bleach (12.5%) this morning about 7:30 EST and at 2:30 the level was 0. I also added some acid (approximately 24 oz) since I'm trying to bring my TA down and added about 10 lbs of calcium. All 3 items were added in the same 15 minute period this morning. My levels are all good. The TF-100 kit is new. Why suddenly is the chlorine dissipating so rapidly? I don't want to just dump a bunch of bleach in right now if I should be looking at something else other than something organic in the water.

pH - 7.2
TA - 110
CYA - 30
Calcium - 275

 

[Jimrahbe]

v,

You really should never let your FC drop below the minimum.. For a CYA of 30 your minimum is 2... see this chart.. [FC/CYA][/FC/CYA]

You might want to bring your CYA up to 40 or 50 to help keep the sun from burning off the chlorine so quickly.

I suggest that you run an Overnight Chlorine Loss Test (OCLT) just to make sure nothing is in the water eating your FC... Here is how... Overnight Chlorine Loss Test

Thanks,

Jim R.

 

[getreal720]

Also, don't assume that bleach or chlorinating liquid is any "good" either.

The FC content could be much lower if nothing.... if it's a really old batch or it was stored improperly it could be no where near as strong as your thinking it is.
You could afford to try using maybe Cal - Hypo to chlorinate for a few days to see if the FC levels and their dissipation rates return to normal. I'm not saying
it's 100% the answer... but suspect that maybe your bleach isn't as strong as you think it is.

I have some very sunny days here in the summer, and my pool never eats a crazy amount of FC. I think it's normal consumption never went above 2 ppm really.

 

[duraleigh]

It is mandatory that you keep adequate bleach (chlorine) in your pool.....regardless of the consumption.

In your climate, I would calculate and add enough CYA to get to 50 ppm. That will slow the FC loss considerably.

generally needing to add 1 or 2 gallons per day

thats pretty erratic. Are you using PoolMath to calculate your doses?

 

[s_vidden]

It is mandatory that you keep adequate bleach (chlorine) in your pool.....regardless of the consumption.

In your climate, I would calculate and add enough CYA to get to 50 ppm. That will slow the FC loss considerably.

thats pretty erratic. Are you using PoolMath to calculate your doses?

My CYA recently dropped to below 30 ppm...(maxed out the TFTestkit vial) due to some extreme rains in June. Started burning almost a gallon a day. Bumped my CYA back to 42 ppm (rounded to 50) and my liquid chloring useage (12.5%) has reduced to half gallon. Typical for 21K gallon pool. My guess is the same. CYA has dropped too low.