Thanks To All!! Clear Pool At Last

[karenkr]

First I want to thank all of you-----I finally have a beautiful clear pool. Had my doubts but kept plugging away with the bleach and just like you promised I finally have a Swimming Pool again.
Do have a couple of questions though. Even after draining my pool about 1/2 way I still have a high CYA of 120. I know I should drain again but Im going to try to just maintain a higher chlorine level for right now.
Pool readings: Chlorine: 10
Ph: 7.8 (is this too high)
TA: 160
CYA: 120
Are my readings ok???
Also have a really dumb question. Will calcium hypochlorite raise my cya?? The reason Im asking is our ACE store has a good sale on it and right now it is cheaper than bleach----but I do not want to raise my cya. The package reads calcium hypochlorite 62.4%, other ingredients 37.6% , Available chlorine 60%. Would it be ok to use or should I just stick to bleach?
Again THANK YOU!!
Karen

[aylad]

Cal Hypo will not raise your CYA, so if your Calcium readings are low, it would be a good alternative for you for now. You don't give a calcium (hardness) reading, though--you don't want to go above about 400 because you'll start hving cloudy water problems, especially with the pH and alk that high. (Hardness issues aside, pH of 7.8 is on the high end, but it's okay--same with alk of 160...........it's not okay if you have high calcium levels, though, because the calcium will tend to precipitate out of the water and cause milky looking pool.)

Janet

[karenkr]

Thanks for answering me.
I tried to test my hardness. Put 5 drops in and nothing happened. Did not turn red. Went ahead and added 30 drops of titrant and still no color. Does that mean I have too much hardness or none? If too much what do I do?
Thank you
Karen

[aylad]

Sounds like you don't have any....cal-hypo shouldn't be a problem for you.

Janet

[karenkr]

Thanks
Sure appreciate your quick answer. Should I try to lower my ph some? re-tested ph 7.8, TA 160, Cl 8
Karen

[chem geek]

You can try, but you may find that your pH will want to drift upward because of your high TA. My guess is that you'll have a hard time getting much below 7.5 and staying there without fighting a rising pH (and adding acid to compensate). There isn't a real problem operating at the higher pH you are at though your chlorine effectiveness is slightly reduced (not that much though, due to your CYA).

Speaking of CYA, your CYA is too high at 120. Yes, you can try and maintain a minimum chlorine level of 8, but if you pool is exposed to sunlight, then you'll be fighting loss of chlorine every day. I know you said you already drained by half and wanted to try and keep the chlorine level up, but if you find that you have a hard time doing that (because your chlorine loss is high and you are adding lots of chlorine every day), then read on.

My suggestion would be to partially drain and refill your pool water (again). This will lower the values of all of your pool chemicals including CYA and TA unless your fill water is high in TA (i.e. is very hard water). You can use your test kit to test your fill water, mostly for TA and CH (there shouldn't be any CYA in it). Since there wasn't any CH in your pool, I would guess there is no CH in your fill water and usually that would mean your TA in this fill water would also be low (which is all good).

Anyway, that's my two cents...for what it's worth.

Richard

[karenkr]

Thanks for the info.
Had thought about draining some of the water but right now we are on a water ban. I live in Oklahoma and this is the driest year we have had in a long time. I can get by on adding small amounts of water but not enough to re-fill. So for right now I have to contend with the high CYA. Next year will be different though-----------no more tablets for me!!!!!
Question: Since no hardness shows up should I do something about that? Do I need to add something?
Thanks for the help.
Karen

[chem geek]

Karen,

Is your pool plaster or does it have exposed grout anywhere (on a tile line, for example) or is it a vinyl lined or fiberglass pool? If it's a plaster or exposed grout pool, then you definitely have to have calcium in it, otherwise your pool water will slowly dissolve your plaster and grout. If it's vinyl or fiberglass, then you don't need the calcium.

By the way, if your pool is plaster or has exposed grout, then any dissolving of the plaster or grout would result in your pH and alkalinity increasing over time just as if you were adding soda ash (calcium carbonate) to your pool. Since you have high pH and alkalinity, perhaps this is what was happening with you (which wouldn't be good -- if your pool surface is plaster, does it look pitted or has it been getting rougher over time?).

Richard

[karenkr]

My pool is gunite--is that the same as plaster? The pool is an older one, I would say 15 plus years. We were told earlier in the season by my ex-pool guy that we needed new gunite at about $6000 --cant afford that at this time so we are making do with what we have. There is some pitting-nothing bad that I can tell though. What is wierd though is that if I check with strips it shows my hardness at 400, but with the drop kit the water does not even turn red.
Just re-tested my hardness with drops(added cal-hypo last night) and the water turned a very light shade of pink. After 40 drops of titrant the water turned a very light turquoise blue. So now maybe I have some hardness? When I add the 5 drops it sinks to the bottom and I have to stir to mix--is this ok?
Thanks
Karen

[chem geek]

Yes, gunite is technically sprayed concrete, but the calcium carbonate that we are concerned with is part of Portland cement that is part of concrete, mortar and most grout. So I've been loosely saying plaster/grout when I should really be saying shotcrete/gunite/concrete/mortar/grout/plaster (what a mouthful!). Technically, a pure plaster (not concrete plaster) is calcium sulfate (usually derived from gypsum) which also needs calcium for equilibrium, but sulfate as well (at any rate, this kind of pure plaster isn't in pools -- only concrete plaster is). But I digress...

My understanding of typical in-ground pool construction (and my understanding is quite limited) is that they dig a hole in the ground, place rebar, spray with gunite (actually spray concrete in a mixing technique that has this named gunite) and then finish with a concrete plaster surface with some tile at the top that has grout in between. So technically, the sprayed concrete (gunite) and the concrete plaster on top of it as well as the grout between the tiles contain calcium carbonate. So yes, your pool needs calcium (and carbonate, which is most of your TA) in the water.

As for your calcium test, I don't have the Taylor guide booklet with me, but I do recall it saying something about certain substances interfering with the calcium test, but I don't recall what it is. Perhaps someone else out there on this forum knows what can "bleach out" the calcium test. At any rate, it does appear that you have calcium in your pool and yes, in my experience the deep red drops usually sink to the bottom so you have to mix (shake) to get the pinkish color. If you are doing the test I believe you are, then the 40 drops means 400 ppm calcium hardness which would normally be OK except that you also have high TA (160) and high pH (7.8). That combination in theory gets you close to scaling (precipitating) calcium carbonate though I've learned that this often doesn't happen and you would likely see your water get cloudy first.

At any rate, we've already talked about you doing a partial drain and refill to try to lower both your CYA and your TA and this will also lower your CH as well, so that's really the easiest way to get down to better numbers. After that is done, then you can repost your results and we can see what else needs to be done, if anything. It may be that you will need to get your TA down even more (to 80-100), but work on one thing at a time (i.e. partial drain and refill first) or else you'll go nuts trying to simultaneously get it all right!

[EDIT] WHOOPS! Reread your post about the water ban. OK, here's what you can do instead. Follow Ben's procedure for lowering TA by first lowering pH (by adding acid) and then aerating. By significantly lowering your TA to 100, you should be able to have your pH remain somewhat stable at 7.5 and this combination will be better for you given your CH of 400 (it should also have pH rise less and have you adding less acid). With your high CYA, you will need to keep your chlorine up according to Ben's Best Guess CYA chart, but you'll have to live with that (and adding chlorine regularly) until you are able to partially drain and refill your pool again.[END-EDIT]

Richard