No CYA in pool, redux

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Originally Posted by PoolDoc

If you used the 'cloudy water' test for CYA (melamine precipitation), and got a zero result . . . it's zero. The remaining question is, did the CYA go to nitrogen gas (no problem) or ammonia? If it's ammonia, you'll see high combined chlorine levels, and low free chlorine. You have to use a DPD test kit to get good info on that.

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I have the same problem: my CYA went to zero (using your test kit and the melamine precipitation test) and I have a high combined chlorine level. This was tested after running the pump for about 24 hours, so there are no issues with uncirculated pool water. My question: what do I do now? I added a bunch of chlorine and the free chlorine level is about 1 while combined is 3 (the daily test kit shows 1 even though I thought that this measured total chlorine).

All other levels are good (alkalinity, pH, calcium).

Hi Steven:

Clearing up ammonia or urea from CYA is straight forward, just slow and expensive.

1. Add borax till your pH is at or near 8.0
2. Add plain 6% household bleach --IN THE EVENING -- in 10 ppm chlorine doses (~2 gallons per 10K gallons)
3. Skip dosing if TC (total chlorine levels) approach 20 ppm.
4. Continue holding pH high and adding 10 ppm chlorine doses till CC is less than 1.0 ppm, and chlorine loss overnight is less than 1.5 ppm.

You can swim while this is going on, BUT the water may be irritating, especially to eyes.

You'll have to keep your chlorine level at shock level as consistently as you can until you can go overnight without losing more than 1ppm of chlorine and your CC reading is no greater than 0.5ppm. It can take a lot of chlorine to get rid of the ammonia that is a byproduct of CYA degradation over the winter. Sometimes you think you'll never be able to quit dumping in bottle after bottle of bleach and then one day, the chlorine will hold!

By the way, it is best to start your own thread instead of tacking onto somebody else's. It gets kind of confusing to be helping with two pools within the same thread. Good to see you back on the forum this year!

I'se moved it . . .

Thanks for your welcome. I've recommended this site to two friends who bought houses with pools in the last year. I couldn't say enough about how much I've learned here, at PoolSolutions, and from the various linked materials.

Sorry about confusing the posts - I actually thought that it made sense in the context of the other poster's question since Ben created a framework in his response but didn't fill it in. This is the first pool chemistry problem I've had.

Anyway, is there a reason that you and Ben suggested that I use liquid chlorine instead of granulated? I have *lots* of granulated.

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Originally Posted by StevenHB

Anyway, is there a reason that you and Ben suggested that I use liquid chlorine instead of granulated? I have *lots* of granulated.

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Yeah. Bleach is less complicated. If you have cal hypo, that will work well if you have a sand filter. With a DE or cartridge filter, it's a little more complicated.

If you have dichlor, we need to work out how high you want your CYA to be, and make sure we stop using dichlor before overshoot.

So do this:
1. Post your pool info (gallons, surface type, make/model of your pump/filter, other equipment) in your signature (Link in MY signature)
2. Tell me what kind of granular (dichlor or cal hypo) you have, and how much.

And, then we can go from there.

Sig updated with more information than you need (I uploaded all details a long time ago to Google Docs so I could find it anywhere/anytime).

I have ~60 lbs of cal hypo (I usually buy 50 or 100 lbs once a year).

I should probably also tell you that I added 3 lbs of granulated CYA last night.

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Originally Posted by StevenHB

added 3 lbs of granulated CYA last night.

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Hm-mmh. Via your skimmer?

Ok -- like this:

1. No more CYA, till you can hold a residual overnight, and your CC is 1.0 ppm or less.
2. FIVE gallons of plain 6% bleach each EVENING through Thursday PM
3. Friday, clean your filter -- you have to get any remaining CYA OUT of the filter.
4. After the filter is clean, make 1,000% sure that there is no trichlor, no ionizer, no NOTHING except pipe and pump between the skimmer and the filter. Note your clean filter pressure.
5. Dose with 5 lbs (6 cups) of cal hypo added SLOWLY to the skimmer. Add the first cup, and wait 30 minutes to see if you forgot something. If there's still CYA in the filter, it will sound like you are cooking popcorn in it -- when the CYA + cal hypo particles DETONATE! Usually, this doesn't damage the filter, but it's MUCH better to avoid this.
6. Repeat EACH evening. Clean the filter by opening and washing it out, when the pressure has gone up 10 psi.

Several comments:

=> If you haven't already raised the pH, per instructions above wait to do so, and let me know CURRENT pH
=> Adding via the skimmer like this, will leave all the calcium from the cal hyp ON the filter. You will have to physically remove it from there.
=> Cal hypo reacts badly with almost everything, except water, borax and soda ash. Do not mess up -- NOTHING between the skimmer and the filter except pipes & pump!!!!
=> Following this process will actually REMOVE calcium from your pool water, at the cost of your having to clean your filter more.

BUT there's a next step, involving washing soda. I need to hear from you on this stuff first, however.

Yes, CYA was added via skimmer. There is *nothing* but pipe and pump between the skimmer and the filter. I have no chlorinator, ionizer, or other accessories. I'll check the pH tomorrow but it was 7.3 or 7.4 last night. Definitely won't be adding bleach tonight.

I see you cleaned up my sig. Thanks.

Ok pH was 7.5 this evening. I added the first five gallons of 6% bleach (I learned that there's 5.25% bleach, too).

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Originally Posted by StevenHB

(I learned that there's 5.25% bleach, too).

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Yes, and there is 3% sold as well. You have to check the labels.

Things seem to be improving more quickly than you suggested they would. This morning I had:
pH: 7.5
FC: 12
CC: 0.5
CYA: 20

Is there a reason to continue with the program you outlined above?

No, it looks like you can do what you want.

You may wish to consider doing this:

1. Go to Sams Club and get their 24 pack of PoolBrand dichlor shock.
2. Use those packs to chlorinate for the next 2 - 3 weeks. Doing so will ALSO add about 50 ppm of stabilizer to your pool
3. Use borax to keep your pH 7.4 - 7.8 (Dichlor has no initial effect on pH, but a strong acidic effect, as it's used up)
4. Raise the pH to near 7.8, when the dichlor is gone.
5. Make sure your filter is full of sand and working properly (you can do the 'DE test' to check). Note the 'clean pressure' on your filter.
6. Begin using the cal hypo in your skimmer.
7. Backwash when the pressure is up 6 - 8 psi

Adding cal hypo this way will 'auto-balance' your pH / TA / CH. The cal hypo 'debris' will end up on your filter. If your 'balance' (Saturation Index) is low, some of the calcium carbonate will dissolve, raising pH, TA, & CH. But, if your balance is high, excess calcium in the water will deposit on the existing calcium particles in your filter.

Also, the fine calcium powder tends to adsorb oils and debris from the water, and then remove it from the pool, when you backwash. Using this method on overloaded commercial pools, I've been able to achieve some remarkable increases in clarity and water quality.

Of course, you WILL need a K-2006 kit or equivalent, so you can keep an eye on the process.

Thanks, Ben. I have your PS-232 (I think) from some years ago so I can test all of the things that you mention.

For what it's worth, I have a DE, not a sand filter.

Yeah, the PS-232 was mine. I'm amazed at how long some of those have lasted!

Anyhow, you can do what I said about the cal hypo with DE, but you'll have to clean your filter more than you would otherwise. The problem is, you'll end up with really high calcium in your pool if you use cal hypo as described on the product label.

I've replaced some of the solutions, but it's fundamentally a pretty solid plastic box.

Just out of curiosity, why are you recommending that I do these things? What's the benefit?

Which things?

You recommended that I use dichlor to add CYA (rather than more CYA into the skimmer), raise the pH and dump cal hypo into the skimmer. Is this all to build a reservoir of calcium carbonate in the filter, which will then buffer the TA, CH, and pH?

I was mistaken, my kit is a PS-233.

Sorry, Lucy, I 'splained all I'm gonna 'splain.