Are we not adding enough bleach?

[watson524]

Recently had to switch to 8.25% bleach because of murky water (due to be changed) and the CYA level creeping up high (currently 85) and us newbies not accounting for needing to have a higher FC to combat that until we dump.

Got the water cleared up thanks to all the help here. Friday nite (4/24/15) the FC was 15ppm. We went in the tub for 40 minutes (so 1.2 person hours). Added 1/4c of 8.25% bleach afterwards which according to pool math should have taken it up 5.3ppm.

Last nite we tested at 7:45pm and the FC was 9.5ppm.

So if it was 15ppm on Friday nite before soak and then we added enough bleach post soak to take it up 5.3ppm that should be roughly 20ppm and then almost 24 hours later it was back to 9.5ppm. What exactly does that tell me? Did that 1/4c not do enough for us to deal with general losses plus bather load cleanup?

So after reading 9.5ppm last nite, we added another 4oz of bleach at 10pm which should have put us back in the 15ppm range. Didn't go in the tub.

Just now did our weekly testing at 1:45pm with these numbers:
FC: 7.5ppm
CC: 0.2ppm
CH: 100
Ak: 70
pH: 6.8 (tho no aeration so I'm somewhat ok with is being low I think)
CYA: 85 (I know this is too high, we just don't have time to dump right now)

So in 16 hours with no one in it, the FC came down by 50%?? That seems bad but perhaps it's still cleaning up little bits of things even tho we shocked the heck out of it when the water was cloudy. On the CYA chart 7ppm is the minimum with 10ppm being the target so I'm thinking I should add in 2oz of 8.25% bleach to take the FC up 2.7ppm. But then I don't know how much to put in after our soak (probably 1 to 1.2 person hours) tonite.......

Thanks for helping me interpret this stuff.

 

[pooldv]

The most helpful thing I did maintaining pool and tub is write everything down for a while to see what the real world result is of the theoretical. Lots of things impact how much chlorine it takes to clear bather waste.

So, for a while test, add, test and test again the next day. And write it down until you see a pattern.

- - - Updated - - -

PH should be 7.2 min.

 

[pooldv]

Had a chance to reread, based on what we know so far I would add 10ppm after the 1ish hour tonight. And remember you are safe up to shock level of 31+.

The goal is to add enough FC after the soak to be above min 24 hours later or next time you plan to check.

 

[watson524]

Ok I'll add the 7.5oz of 8.25% bleach tonite when we're out. So you're thinking that would clean up what's in there (cripes are we not showering off enough before going in??? I don't even wear lotions and perfumes) and then tomorrow nite same time I can check it and see what it's at? Is it worth checking it again say 12 hours later or any time during the day tomorrow? thanks!

 

[pooldv]

LOL! People are kinda messy! Especially in a few hundred gallons of water. Sweating and what not. Good that you aren't wearing lotions, those are another problem. We're sitting in the tub right now, been in a couple hours having drinks and watching hgtv and watching it rain. The sooner you drain and refill and add the borax the better too.

Sure, a little more testing in the beginning always helps to understand your water chemistry better. It is easy to manage once you get an understanding of how your tub works. We changed the water a month or so ago after about 10 months just because it seemed like we should. Our tub water is really nice! Clear, sweet smelling, all good! Oh, we've got some epsom salt too. ahhhhhh!

 

[watson524]

Hopefully next Sunday we'll get to do the ahh-some, drain and refill if no other nonsense comes up before then.

I didn't realize you could put epsom salt in hot tubs without screwing up the chemical balance. We've both runners and people are always saying how good epsom salt soaks are.

 

[pooldv]

Good luck with nonsense avoidance! Yes, we've had epsom salt in our tub and pool forever. It does seem to help. We've got 25lbs of dead sea salt in our pool, too. It didn't make us feel worse!

 

[watson524]

Nonsense avoidance seems to be sometime I've never mastered unfortunately.....

Tested about 9am this morning (so about 11.5 hours after we added 10ppm last nite) and FC was at 12ppm so I'm going to test about 9pm tonite to see what the total loss in 24 hours was. When the CYA gets high, I know it needs higher FC but does it also use up the FC faster? I figure higher is needed to be as effective but is it also needed because use rate goes up?

 

[pooldv]

No, FC usage is not higher with higher CYA. If your tub gets sun, then sun will consume some FC. All things equal your daily FC consumption should be the same no matter the CYA level. It just needs to be higher with higher CYA.

 

[watson524]

Huh ok. Tub sits in direct sun most of the day (when we actually GET sun) but it's always covered except when we're in it at nite so I guess the sun isn't contributing. So 17.5 to 12ppm in about 11.5 hours so just over 30% which is why I want to test again at the 24 hour mark since it seems like we'd be in the 50% loss range. Once we dump the water and start over, I'm definitely going to be doing an overnite loss test. And I'm writing everything down in my note book we keep for the tub so I can keep track of all this.

 

[pooldv]

In the sun with a cover doesn't count as in the sun. I mean sun shining on the water burning off the FC, like in a pool. I wouldn't focus too much on daily FC use as a percentage of what is in there. It is more about how many ppm get consumed with bather/hour load and without and replacing that every day or two to keep the FC at or above target and definitely above the minimum for your CYA level.

 

[watson524]

Will be interesting to see if we have the same bather load in people/time how the FC gets used up. I would expect for consistency in people and time the FC usage would be the same. So I'll just keep tracking in the notebook and see what happens. If we end up needing say 1/4c / day when used and (arbitrarily) 1/8c / day when not used, it might go through clorox pretty quickly and better head to WalMart to stock up.

 

[watson524]

Checked it at 8:45pm tonite and it was down to 7ppm FC. We went in for 1 person hour tonite so I gave it 10oz which should have taken it up 13ppm to 20 and when I tested 20 minutes later after running the jets, it was 19ppm so pretty close (and I figure it was less than 7ppm when we got out since some got used up just with us being in there). So I'll see how that is prior to soak time tomorrow nite.

One question, the water is definitely nice and clear and sparkly but it seems to have a lot more "fiz". It's not soap bubbles and it's not foam, but it happens more with the air jets on and goes away as soon as they're off. Is this just the nature of older water maybe or something to do with the bleach?

P.S. My speed stir came today too. Total gadget geek joy! LOL!

 

[pooldv]

LOL!

We get a little of that foaming sometimes. More skin oils and human pollution. Chlorine will eat that up. I seem to recall that low calcium level can contribute to foaming as well. Bringing CH up to 130-150 could help. But, I wouldn't bother until after you drain and get everything right. Sounds like you are getting it figured out!

 

[watson524]

Yep slowly but surely thanks to all the help here.

My husband isn't thrilled with the chlorine smell when he opens the cover or gets in the shower after (it steams off him) but while we're in it it's ok. The CC is 0.2 so it's not coming from that, perhaps just the high level because of our CYA being so high or is relative (i.e. chlorine will smell at lower levels too as a proportion of the CYA)?

 

[pooldv]

There shouldn't be any chlorine smell. Maybe it is related to mps and prior maintenance chemicals? Or if there are spikes in CC. We have virtually no chlorine smell ever in tub or after. I think the sooner you drain the better.

 

[watson524]

It's possible he's just overly sensitive to it. I've been around tubs/pools that STINK of chlorine and this is nothing like that. And it's interesting since the MPS strips are still reading MPS even tho that hasn't been added in well over a week.

One other question..... Should I put the Borates in (looks like pool math says some Borax and then muriatic acid both which I'd have to go get) between now and dumping or ok to just wait and do it after we dump? Just not entirely sure what the Borates do.

 

[pooldv]

I would say yes. Borates make the tub extra nice, smooth and silky. Hard to describe but noticeable.

 

[gtemkin]

Can you let us know what type of test kit or testing you've been using? The 0.2 value you mention for CC seems suspicious since it not in the 0.5 increments we commonly see with the recommended drop based tests. Thanks.

 

[watson524]

Can you let us know what type of test kit or testing you've been using? The 0.2 value you mention for CC seems suspicious since it not in the 0.5 increments we commonly see with the recommended drop based tests. Thanks.

I have the Taylor K-2006 kit. If you take a 25ml sample the drops represent 0.2ppm of FC or CC. If you use a 10ml sample, the drops represent a 0.5ppm