Cloudy, then green with a never ending chlorine demand

[CarlD]

What is your CYA reading? With that, we can tell you what an effective chlorine level is.

[cleancloths]

What is your CYA reading? With that, we can tell you what an effective chlorine level is.

Need to go out and get that tested. I did not add any last year, and only used about 20 pucks all year. When this mess started I added 4 pounds, but that is all I have to go on right now. I just don't understand why the pH keeps dropping.

[cleancloths]

Just checked pool this morning after making yesterday's additions:

Cl Free 0.75
Cl total 1.5
pH 7.3
Total Alk 100

So, except for chlorine it is looking much better. Added another 3 gallons bleach.

I'm going to take a sample to the "pool store" and have them test it today to find out what the CYA level is.

[cleancloths]

So I went to the pool store and had them test the water. They have a fairly sophisticated setup. They have a bunch of square-sided "testtubes" that each have powdered reagents in them for a set test. They use a pipet to inject water into each one and then use a computer controlled colorimeter to directly measure and record the readings into the computer. Any way, here is what they came up with:

Chlorine Total and Free both 3.8
pH 7.7
Alk 90
CU & FE ~0
Stabilizer 10 ah ha!, BUT wait...

How can we believe the stabilizer is only 10? Wasn't it on Saturday that I added four pounds of CYA to my 20x40 IG pool. Doesn't that increase the level by about 30 all by itself? So, now what????

[Watermom]

What is your pool volume? How did you add your cya and if you added it to your skimmer to dissolve in the filter, have you backwashed any?

It may be that it just hasn't dissolved yet. It takes a long time. Or it may be that their result is inaccurate. CYA readings seem to be one that pool stores often get wrong.

Is the pool looking better? Keep at it. You're doing the right things.

[cleancloths]

Pool volume is about 33,000 gallons. Added CYA to the skimmer and have not backwashed, did that the day before adding it. I know they often do things wrong, but this store is fairly good. The setup is they have a testtube that is sealed from the factory for each test. They then pipet the water in and insert the tube in a colorimeter - so no highschool dropout is trying to read colors - its all machine read. So, I will go with your guess that it is not fully dissolved yet.

The pool is looking much better. It is mostly clear in the shallow end and only slightly green tinted in the deep. But the rate of improvement has dropped. There is no slipperyness on the wall or floor.

[Watermom]

Keep hammering it with bleach. It will clear!

BTW --- I just checked and 4 lbs. of cya in a 33,000 gallon pool should take it up to about 15 ppm, not 30. So, your pool store's reading is probably right. But, if it were my pool, I'd still wait a few days before deciding to add more.

[chem geek]

I don't care how sophisticated their equipment may seem, but most pool stores test inaccurately, especially for the CYA test. I don't know whether it's training, lack of calibration, use of old reagents, or what, but you should use you own good Taylor K-2006 test kit for doing water chemistry tests. Nevertheless, they could be right about this one if the CYA didn't fully dissolve.

It can take several days to a week for the CYA to show up in the tests, depending on how quickly the CYA dissolves. It is slow to dissolve -- the fastest method has pure CYA hang in a sock or stocking over a return flow. Next best is in a skimmer sock or equivalent in the skimmer (careful -- you have to have alternate flow to the pump so you don't crack your skimmer). If you just add the pure CYA directly to the skimmer to get caught in the filter, then you should not backwash for a week and it will be slower to dissolve since the rate of water flow is quite slow when dispersed in the filter.

There is a liquid CYA called Instant Pool Water Conditioner that dilutes into the water right away, but it's about twice as expensive as pure CYA, though it also has the benefit of being roughly pH neutral.

[cleancloths]

Thanks ChemGeek, maybe it just hung up in the filter. Its been another bunch of days and the pool is basically the same. The shallow end looks great but the deep end has a slight green tint. I got really pissed off last night and added three bags of shock to it. Just looked out my window and there is no visible change - will go out in a little while and take some readings.

Is it possible whatever is green is too small to be taken out by my DE filter? Alternatey is it possible that whatever it is might be in the filter and I could get rid of it by backwashing and flushing it out of the system?

==================================EDIT============ ========

Just went out and measured. FC and TC as measured by my kit that uses three reagents that turn the water purple was about 4 each. Just for (****s-and-giggles) I tried it with my old kit that just uses the one reagent that turns the water yellow and it shows up as 10ppm or higher. Now that makes no sense.

May order 180 yards of dirt today and just fill her in

[CarlD]

Hate to see you getting so frustrated. There's almost nothing that normally happens to a pool and its water that the gang here cannot figure out.

You, though, need to keep at it, hammering it with chlorine and daily backwashing, brushing, and vacuuming to waste.

Since you are already up to your ears in it, I suggest you spend the $50-$75 on a FAS-DPD chlorine test kit. There are numerous references on PF for where to find the Taylor K-2006 kit inexpensively or you can go to the Leslies on-line web site and get their clone: The FAS-DPD Service Test Kit. It's the same as the Taylor but it's in a Leslies box.

FAS-DPD will give you a sounder reading on your FC and CC (you'll calculate TC = FC + CC).

It will be far cheaper than 180 yards of fill!

Remember: The most important ingredient you need is P.O.P.P.--Pool Owner Patience and Persistence!