How much bleach is too much?

Jul 3, 2017
3
Langhorne, PA
Hello incredibly knowledgeable people! I am a long-time (well, 2 year) lurker, trying to get serious about doing my own testing and all this summer. I never owned a pool before we bought this house three years ago. I have read Pool School and the article on SLAMing, but have questions. I hope these aren't too rudimentary, please feel free to direct me to threads I've missed if this has all been covered elsewhere.

My main issue is that despite trying my best to follow your guidelines, I can't seem to get any sort of FC reading to stick. Right after I add a 148 oz tub of bleach I get a nice FC of 12 or so, but even two hours later I'm back to 0. My CYA is about 40. I've ordered one of the fancy FAS-DPD kits I saw recommended here, so don't have anything more precise to report about CC until that arrives and I figure out how it works. Right now I'm just using test strips. The strip also tells me that my pH is WAY low, like 6.6. I had some soda ash sitting in my chemical supply area from the first year we had this house, so threw that in (about two pounds, which the pool calculator tells me is not enough, but thought I'd check in with you guys before heading out to buy anything) and am waiting to see if that helps. My TA and hardness were both in the target range the last time I had Leslie's test my water (3 weeks ago). But as I said, I'm trying to get away from them and be more independent and spend less money. Leslie's did say I had a slightly high nitrate reading.

So all that being said, I've now dumped 4 of the 148oz bleach tubs into the pool (3 in the past 24 hours) and I'm starting to worry that I'm poisoning my children and still not getting any chlorine reading. What am I doing wrong? The big thing I fight with this pool is it is almost totally tree covered so it gets loads of leaf matter. I scoop it and vacuum daily, but there's almost always something floating in the pool. Am I just doomed to struggle with this given how much organic matter is always in the pool? Last week a frog was swimming around happily, this has really gotten out of hand.

Oh, final bit of info, the pool did look greenish (not horrible, just a bit) in the deep end this weekend, but is beautiful and clear now. I have brushed the heck out of it, and see no lingering algae.

Thank you so much for your help, and I will get you better numbers once my test kit arrives today or tomorrow!

Amy
 
If the pool is really green and murky, then the bleach is all getting used up. Almost as fast as you can pour it in.

If the water isn't so bad, and you're using test strips, it's possible the chlorine level is really high and is actually bleaching out the test strip.

That's why the SLAM article specifies a FAS-DPD test kit as a prerequisite.
 
Yes, 8% chlorine bleach.

- - - Updated - - -

And the pool is not at all green and murky (anymore). It's crystal clear, but most mornings I find some algae has developed in the corners that I dutifully scrub away, so I'm assuming I am not done SLAMing. I'll check back when my kit arrives, but I don't think it's a bleaching out problem because it is bright purple about 15 minutes after I add 148 ounces of bleach. Then 2 hours later it's back to being straight white. It wouldn't go the other direction would it? Thanks for your quick responses!
 
Your bleach is being consumed by the algae, and your stabilizer is probably not what the strip says it is. Add a jug of bleach a day to keep things in a holding pattern until your test kit comes in and we can know for sure what the chemical levels are. You can add the bleach in the evening after the kids are done swimming for the day.
 
Thank you! This is what I needed to hear, I really appreciate it. I just threw a jug in around 7 pm following your advice. Water looks great, but there was already algae growth in patches for me to brush and I had just brushed this morning. I'll repost when I have good numbers. We will feel good swimming tomorrow on the holiday while I work to get this under control.

Your bleach is being consumed by the algae, and your stabilizer is probably not what the strip says it is. Add a jug of bleach a day to keep things in a holding pattern until your test kit comes in and we can know for sure what the chemical levels are. You can add the bleach in the evening after the kids are done swimming for the day.

- - - Updated - - -

I usually run it from 10 am to 6 pm, but for the past three days while I've been intensively working the SLAM process I've left it on 24 hours/day. Is this the right thing to do? How many hours should I run it once I'm free of algae?

How many hrs are you running your pump?

- - - Updated - - -

Also - should I deal with the FC before I tackle the pH? Or I guess I should get a good CYA reading before doing anything else regarding the pH?
 
First, post up a full set of results. We'll be here to guide you. Let us know if you have any trouble with any of the tests.

The CYA test is a light sensitive test, back to the sun, vial at waist level. You can pour the contents back and forth. I like to pour it to the first line, glance, pour it to the next line, glance, etc.

This is the format we like to see:

FC
CC
PH
TA
CH
CYA
 

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