CYA off chart...high?

[reacherAZ]

Pool Stats: (1997) 21.3k IG, Sta-Rite Sys 3 600sq ft Filter, AO Smith 2.2hp single speed motor, in-floor clean jets.

Test results: 12 FC, 2 CC, 7.6 PH, 130 TA, 750 CH, CYA is off chart w/ K-2006...1/4" below 100 reading.

Location: AZ Desert Pool Temp: 88 to 92 in season.

Sanitation History: trichlor tabs and dichlor shock

Goal: Transition to BBB method, reduce CYA and Calcium Hardness, if recommended.

Details: took over pool last season, after many years of pool service. Plan to drain 1/2 pool and refill, any
thoughts? BTW, fill water is testing at 250 CH. Any rule of thumb on amounts of BBB to stock?

Any and all guidance much appreciated.

[kelemvor]

As far as the CYA goes, I believe you have two options.

1. Do a partial drain and refill to reduce the CYA level. This is the only method to remove CYA from water. I'm sure it's not a very desirable option given your location.

2. You can successfully manage a pool with a high CYA. You still need to know what the CYA actually is, and you still use the best guess chart and every other part of the BBB method.

If you want to use option 2, you need to get some distilled water from your local grocery. Dilute some pool water 50/50 with the distilled. Perform the CYA test on that water, multiply the result by two. Hopefully your CYA won't be over 200, if so - further dilute, retest, and multiply appropriately. Personally I'd give up on option 2 with a CYA over 200 and bite the bullet on a little refilling.

As far as chemicals to keep around, that depends on how often you make it to the grocery store. I generally try to keep a month or less worth of most chems. Liquid chlorine/bleach doesn't keep all that well so I would not buy a huge amount unless you're planning to use a lot.

Both dichlor and trichlor add CYA to your water. If you weren't already aware, that's probably where you got into trouble with the CYA. You should immediately discontinue their use until such time as you want to increase your CYA level again. Nothing but bleach, or "Liquid Chlorine" for your sanitation. Those are the same thing, except liquid chlorine is usually sold at a higher concentration.

[PoolDoc]

membership upgraded.

regarding stocking "BBB" -- don't. Bleach, Borax, & Baking Soda is more a symbol, than a set of instructions. We rarely tell people to use baking soda, because relatively few pool owners need higher alkalinity levels. We often tell people to use borax, but only when they need to raise their pH. And, when we recommend bleach, it's often not because it's "best", but rather because it's "best" when we don't know much about your pool, since it has fewer side effects.

But, in your case, bleach probably IS best, since the other option (cal hypo) will raise calcium levels. However, you don't want to stock up on it, since it deteriorates rapidly at high temps -- let Walmart keep it stocked in their air conditioned stores!

Regarding draining -- do as you wish. You can learn to manage, or you can lower your CYA by draining and replacing. BUT, if you want to move your pool into the 'conventional' chemistry zone, you probably need to replace 2/3 or more in a single event. Otherwise, you'll STILL have high CYA. Read the Best Guess page, linked in my blue signature block, for a better understanding.

Regarding calcium -- it is possible to lower it -- even remove it, if you want. But it's a bit of a messy process, so I'd leave that alone till you're done swimming for the season.

[reacherAZ]

Ok...getting a better picture of my issues. Appreciate the expert advice, thanks again!

Shocked pool w/ Dichlor prior to receiving responses, new test as follows:

FC 15
PH 7.4
CYA 170

Plan to now manage pool as is until after swim season, temps down, etc.

I've a couple newb questions:

1) Is it safe to add bleach directly to the pool around edges, since my filter returns are in-floor
via cleaner jets?
2) How about adding bleach directly to feeder tank used for trichlor?

Somewhat reluctant to put or around in skimmers (3) which suck direct to filter...degradation?

Any and all advice welcome...Thx.

[PoolDoc]

*DO* pour bleach into the pool; do *NOT* put it in the trichlor feeder. Not only will that feeder not work that way, but if there's the slightest bit of solid trichlor left, it will react VERY BADLY with the bleach.

Adding bleach to the skimmers is OK, so long as there is NO trichlor anywhere that the bleach will directly contact.

[Watermom]

I always add my bleach to my skimmer while the pump is running. Always have. No worries about doing so.

[reacherAZ]

Things seem to be getting better....as follows: using only bleach liquid.
FC: 21
pH: 7.6
cya: 160

As predicted FC drops quite slowly due to stabilizer levels, even with +100* temps & 90* water temps...

A couple questions on testing w/ K-2006...

Seems a waste w/ high FC to use even 10ml level in test, so w/ 5ml test sample, is it right to count drops as actual 1=1 PPM FC? I realize accuracy would depend
on guesstimate on 5ml...

Additionally, when testing pH...sample colors change...ranging up in surprising short time frame...7.3 to 7.6 in 5 minutes. Significance, if any?

Thanks again for the most valuable assistance!

[PoolDoc]

1. You may be able to find a infant dosing syringe at the drug store that will allow you measure a 5ml sample; that would give you a fairly accurate 1 drop = 1 ppm test. Alternatively, you can match OTO tests with the DPD-FAS results till you learn what the colors look like -- obviously, this is rather approximate.

2. High chlorine converts phenol red to chlorophenol red, a different indicator. But when high CYA is present it does so a bit slowly. So, take your INITIAL pH result.

[reacherAZ]

Infant syringe it is..thanks.

added 6 gal 5.5% bleach last evening to raise FC in hopes of eventually removing some darkish mottling that has occurred over past year, or so. I believe it was caused by chemicals w/ copper...only on a few areas around bottom perimeter. Any thoughts on this?

New test this AM:

FC 35
pH 7.6

[PoolDoc]

You can test with a vitamin C (ascorbic acid) tablet -- it will usually lift (re-dissolve) copper or iron. You'll need to let your chlorine drop to, say, 10 ppm before you try that, though. Chlorine destroys ascorbic acid.

That's OK, though. There's no reason to have FC = 35, unless you have some algae. (If you do, brush at it, and it will probably be gone by the them chlorine levels drop.

[reacherAZ]

I've decided to wait on AA process until after pool drain/refill in a month or so. Ideally, my CYA 170, & CH 750 will both be at better levels then...fill water tested at 250 CH. I will test vitamin C on stains once FC comes down, however. I should probably look at heater condition, as well...fairly certain it is original 1997 (RayPak RP2100.) No algae issues since FC levels up.

[PoolDoc]

If you have a heater, then you may have copper stains from low pH eroding copper from the heat exchanger. This is quite common on pool where trichlor has been used, and owners weren't diligent to maintain pH > 7.2