CYA Through the roof?

[aylad]

Just to add a comment, the trichlor is also what's keeping your pH down to the point that you have to add pH ++--by partial drain and refilling, assuming your fill water has a higher pH than that, you'll be correcting that problem at the same time.

I would highly recommend that you stop using trichlor tabs and dichlor shock for the time being, and switch to something else that will not continue to drive your pH down and your CYA up....most of us use plain, unscented bleach that does not add any unwanted chemicals to your pool--it breaks down into chlorine and salt, which is actually good for your water.

Or you might want to consider a salt water generator--I'm looking at adding one to my pool this year because it will make your pool almost as maintenance-free as it can get!

By the way, welcome to the forum!!

Janet

[swilson]

First I want to thank everyone for the replies. I did check and I have been using trichlor so I guess that identifies the culprit. I have actually decided to use the BBB method once I get this cleared up. When I went and bought the test kit I also bought bleach, borax and baking soda in bulk. I am draining the pool to one-thirds to one-half and refilling and then I will test and consult the pool calculator to see what I need to add. I will let everyone know how it progresses.

[Watermom]

Good. Keep us posted. And .... then -- no more trichlor. Trichlor does have its place in pool care. If it is a fresh fill where you know there is no cya, you can use trichlor to add chlorine and cya at the same time, but you have to monitor the cya level as it builds up. Once you hit somewhere between 30-50 cya (I like around 40), you have to discontinue the trichlor.

Did you look at the ingredients of your 'shock'?

[Poconos]

Swilson, what is your water supply? Reason I ask is if it is city water you may have a bill through the roof. You may want to consider using a large plastic sheet instead of just draining-refilling-circulating etc. You can get a large plastic sheet and lay that on the pool. Fill on one side and drain off the other. The membrane keeps the new and old water separated and theoretically you can do a complete exchange without dropping the water level and risking damage to the liner if that's what you have. Sounds like you have a relatively large pool so I don't know if you would have to stick a couple sheets together to get the size. How you would do that I'm not sure. Duct tape may work for a while but maybe there is some kind of adhesive or solvent that would work and hold for the time needed.
Just some thoughts that have been proposed before.
Al

[chem geek]

When I went and bought the test kit I also bought bleach, borax and baking soda in bulk.

Just so you know, BBB does not mean you will normally need to use bleach, borax and baking soda. It is more of a philosophy about testing your water with an accurate test kit so you really know what is in it and then making appropriate adjustments adding only what is really needed, often using less-expensive grocery store equivalents to pool store chemicals. It is a "less is more" philosophy that generally avoids the need for any algaecide, phosphate remover, clarifiers, flocculants, enzymes, regular shocking, etc. It is a program based on careful observation and sound scientific principles rather than marketing hype.

So, in practice, you will be using mostly bleach or chlorinating liquid (whichever is less expensive or more convenient for you) and will not need to use baking soda (to raise TA) very much and may not ever need to use borax (to raise pH) unless you were to use your Trichlor tabs again, say while on a short vacation. It is more likely that you will sometimes use Muriatic Acid to lower the pH. In my own 16,000 gallon pool (shown here and here), I only add 12.5% chlorinating liquid around twice a week (I have a mostly opaque electric safety cover so my chlorine usage is a little less than 1 ppm FC per day) and add a small amount of acid every month or two. That's it -- around $15 per month in chemical costs during the 7-month swim season.

Richard

[swilson]

OK, drained about 2/3 of the pool and filled with city water. Here are the test results:

CYA = 80-90
TC = .5
pH = 7.5
TA = 110
TH = 320

So, based on the pool calculator, it looks like all I need to do at this point is add bleach to get the chlorine level up. Should I only get it to the recommended level of about 4 or should I shock initially. My bleach jugs are 182 oz and the calculator indicates I should add about 1 jug to get it to about 5.5 and 2 jugs to get it to 10.

[aylad]

Wow, if a 2/3 drain resulted in CYA of 80 or 90, then it really was through the roof--no wonder you're having trouble getting it clear!!!
Is your water still green? If it's at all green or cloudy, then you need to shock it by adding enough chlorine to get to 20 ppm. You need to maintain that 20 ppm until it clears, then when you allow it to drop back down, keep it between 5 and 10 ppm--if you go below 5 ppm, you're going to have a really hard time keeping it clear. I know this sounds like a whole lot of chlorine, but that's unfortunately what happens when you have an overstabilized pool, and that's why in MOST cases, CYA of 40 or so is recommended. The good news is that with the stabilizer that high, it will be a longer time in between chlorine additions since the chlorine level won't drop as fast.

Janet

[swilson]

Still working on it but it looks like some progress is being made. Quick question, since I need to keep the chlorine level around 20 till it clears, what it the best way to test that, my kits only go to 5?

[chem geek]

You can dilute your pool water sample with distilled water (tap water usually has chlorine or chloramine in it) and then multiply your result by your dilution amount. So if you dilute 1:1 with equal parts of each, then multiply your result by 2. If you dilute 1 part pool water with 2 parts tap water, multiply the result by 3.

You should definitely get a good test kit. You can get a Taylor K-2006 test kit at a good online price here (the "C" version you refer to is larger in size so is more expensive, but you can get that for a better price here) or the TF-100 you can get here with the latter kit having more volume of reagents so is more comparably priced per test. A comparison of these two kits is in this post. These test kits use a FAS-DPD chlorine test that can measure up to 50 ppm FC, can measure Free Chlorine (FC) and Combined Chlorine (CC) separately and accurately, and can be as accurate as 0.2 ppm when using a 25 ml sample (when shocking, you usually use a 10 ml sample for 0.5 ppm accuracy).