Brand New Fill Water - pH issue

[CarlD]

OK, get a small set of simple test strips and use them to cross-check your OTO reading.

You could also get a DPD test kit and try that.

I'm wondering if there's something else in the water that has caused this...there's something in my memory about a particular metal or salt that alters the color scheme of the pH reading....and it's just there at the edge of my memory....

[elsie]

DPD to check pH?

I used both the old and the new OTO kits and they matched...

It also seems that I cannot keep chlorine in the pool, but I've never run the pool with such low chlorine before (I really don't want to bleach out this new liner). I did just peruse Pamsel's post re: her experience with a new liner and keeping chlorine as well. However my TA is around 140; CYA 50 now.

Last weekend I swapped out a cheap new solid winter cover that within hours of putting on began tearing apart at a seam (lesson learned -- never buy a cheap $50 cover, they're not worth it). I bought a high-quality (expensive) cover from my liner guy and it's much heavier and doesn’t even have seams like that cheap one. But, this is all to say that my cover has been in place and when I viewed the water last weekend while taking the one cover off and putting the other one on with the help of my neighbor, it looked as clear as could be - in fact it could not have looked any clearer. So I find it really hard to believe there may be algae. Water temp I'd guess is around 78.

With the old liner that I didn't much care about because it was entirely bleached out, I would shock to 15 before I put the winter cover on, and over the course of 8 months the ppm would only drop about 11 ppm (to 4 ppm when I uncovered in May). I'm in the south so I don't close my pool and the water does not freeze. I just run the pump on the handful of nights that it drops below freezing to safeguard the above-ground pump pipes.

With the awareness that a high ppm of FC would be sitting in that new liner month after month, I did not dare shock the new water. Each day it seems I put in enough bleach to bring the ppm up to 3 and a day later, it's gone. My liner guy said I don't need chlorine with the cover on, but it makes me unsettled. Can it be anything other than algae? I just can't bring myself to shock it now with the cover on because I don't want the high ppm in there for months on end. Any ideas? Or should I just not worry about it with the water cooling, winter on the way, and the winter cover on?

[elsie]

Well, over the weekend the saga of not keeping chlorine continued. So I decided to bring it up to 4 or 5 ppm, let circulate a day, then test for CC as a way to determine if I had algae or not which would account for the chlorine loss, assuming that if I had appreciable algae which was eating up my chlorine with the winter cover on, it would test postive for CC.

When I stopped at the grocery store to get more bleach, a thought occurred to me: I wondered if my other bleach was simply old, so instead of buying the Publix store brand, I bought a big jug of expensive Chlorox, 6% ($5 bucks). Last night I tested and the water was at 4.5 ppm and no CC. I've got the pump turned off now and will recheck this weekend, but I suspect that the reason behind not keeping chlorine is likely because my bleach was old and ineffective.

[aylad]

I don't know how I missed this thread...but I had a dozen 8 year olds for a slumber party last Friday through Saturday, and then my weekend really got busy....

I'm glad that you got the pH question straightened out and you're right that if you're going to err with pH, then do it on the high side.

Keep in mind also that you don't necessarily have CC when you have algae, especially if it's algae that's not yet visible to the eye. When you added the older bleach, did you test to see that it went up to 3 ppm, or did you just add enough that you knew it would be at 3?

One thing you might want to consider, especially since you're in a part of the country where you don't drain your equipment, is uncovering your pool and shocking it, if you still think possible algae is the problem. The other thing you might consider, if you don't want to shock the pool with the cover on, is to use polyquat, followed by a lower chlorine level when you get ready to close it up. Just a couple of suggestions..........

Janet

[elsie]

So that CC theory of mine doesn't hold water, rats. But this is the thing: the new water was added to the pool in the new, clean/pristine liner, and within 36 hours the pump was running. I chlorinated, but only to 2 ppm. Within two days I covered the pool. The water temp was probably in the high 70's. It just seems very unlikely to me that algae would develop in these conditions. Plus, when I took the one cover off and put the better cover on, the water was clear-clear-clear. It just doesn't seem that the chlorine would be eaten up so fast assuming algae because it would have to be so very low, if it was. Yes, I did test each time, never guessed the ppm.

It would be a good idea to remove cover, shock, let CL drop and recover, but boy, it's a lot of work to remove such a big cover (I have to enlist help of neighbor and though we're both strong, we usually screw up by the time we accordian the thing to the end), and then keeping it free of grass debris and leaves at this point, plus the leaves are starting to come down and with any wind at all I'll just be a slave to the water. And I'm just done (psychologically) for the season. I'm still betting (hoping?) that it was a case of old bleach. I'll run pump tonight and before turning in take another sample and report back tomorrow.

The pH in the meantime, IS holding within range.

[aylad]

Glad the pH situation is fixed....as for the chlorine, if you're finished swimming for the season, just polyquat it, cover it up and leave it alone--you can deal with whatever is under it when it's time to uncover in the spring!

Janet

[elsie]

Yes, so true, that's the option to fall back on. This said, I did check it last night and the ppm's holding at 4.5. I'll check again soon, and expect it to be the same. I *really* do think this was a case of old chlorine now. As always, thanks Janet for your advice. I'll wrap this up with one more post next Monday and hopefully will report 4.5 once again. And now, "sleep, pool, sleep...and sweet dreams along the way."

[chem geek]

I'm wondering if there's something else in the water that has caused this...there's something in my memory about a particular metal or salt that alters the color scheme of the pH reading....and it's just there at the edge of my memory....

According to the Taylor instructions "interference" for the pH test here:

Iron > 10 ppm may cause negative interference.