CYA Levels

[leejp]

According to Ben...

_Stabilizer_____Min FC____Max FC___Shock FC
_______ 0________1________3__________10
_10 -__20________2________5__________12
_30 -__50________3________6__________15
_60 -__90________5_______10_________ 20
100 - 200________8_______15__________ 25

All Units in PPM

I plan to switch to the 3B regimen. Question is what CYA level? Pool is in full sun 8~10Hrs/day in upstate, NY (temps range from high 60s to mid 80s in season). What are the pros/cons of low/high CYA?

[duraleigh]

Hi, Lee,

Without a SWG, 30-50 CYA seems most popular. I'd start low at 30 and then move up a little if you don't think your CL is holding like it should.

If you get a SWG, I would follow Manufacturer's recommendation...usually 60-80ppm.

Dave S.

[leejp]

Hi, Lee,

Without a SWG, 30-50 CYA seems most popular. I'd start low at 30 and then move up a little if you don't think your CL is holding like it should.

If you get a SWG, I would follow Manufacturer's recommendation...usually 60-80ppm.

Dave S.

At 30-50 CYA the min recommended FC is 3 PPM. I don't have Ben's test kit (yet). I'm lookinfg through the test kits I have (OTO... is this a FC or TC measurement?) and 3 PPM is the max the kit'll measure (recommended is 1.0~1.5) Does Ben's kit measure beyond 3 PPMs?

I do have to say I'm a bit nervous... I've had iron staining problems and with high FC, I'm afraid that the iron will be forced out of the water onto the liner. Man I have to get that iron out of the pool!

I guess the danger in running lower stabilizer levels is that the FC will "burn off" quicker on hotter days.

[duraleigh]

Hi, Lee,

Ben's kit has two tests for Cl. A daily, easy one that goes to 5ppm and a drop based slightly more time consuming one that lets you test to shock value (up to 50ppm or so, I think)

I'm beginning to think metal in the water is the new "global warming" issue. I can not remember so many folks having metal problems. Yes, you need to get that resolved....your life will improve.

I guess the danger in running lower stabilizer levels is that the FC will "burn off" quicker on hotter days.

Bingo!! Get the kit (or one that measures FC, TC, CYA, CH, pH, and Alk.) It's the best money you'll spend

[SJohnson]

Everyone should read "WATER CHEMISTRY FOR SWIMMING POOLS"

Here's a link:
http://www.deh.enr.state.nc.us/ehs/chem.htm#ta
There's also a chart on that page that will show you how much certain amounts of cyanuric acid will raise your CYA levels. I've found it handy to keep a printed copy of this information lying around . . . Many people advise dissolving CYA in a sock(pantyhose) placed in skimmer . . .

Also, there was an article by PoolDoc(Ben) on the advantages of high CYA levels, which was interesting but I can't remember if that was on the forum or in poolsolutions . . . anyone remember where that was?

CYA exerpt from "WATER CHEMISTRY FOR SWIMMING POOLS":

"Stabilizer - Cyanuric Acid
Hypochlorous acid is a highly unstable molecule which dissipates rapidly in the presence of sunlight. This results in considerable loss of free chlorine from pools exposed to sunlight. Proper stabilization of chlorine with cyanuric acid slows the rate of chlorine dissipation without appreciably sacrificing oxidation and disinfection activity. Reaction of free chlorine with cyanuric acid produces a form of combined chlorine (chlorimide) which is active enough to aid disinfection and show up as free chlorine residual on your test kit. Proper stabilization requires 30 to 50 ppm cyanuric acid. Outdoor pools should be initially treated with 40 ppm cyanuric acid.

Cyanuric acid dissolves very slowly and is best predissolved in warm water before introducing into the pool. If it is not predissolved it may take several days to dissolve completely. Once added to the pool, cyanuric acid does not dissipate. It is removed from the pool only by splash out and backwash waste. Stabilized chlorine products such as trichloroisocyanuric acid will add stabilizer to the pool and may cause a gradual rise in cyanuric acid concentration. Excessive amounts of cyanuric acid can interfere with the disinfection process and at concentrations above 100 ppm may cause "chlorine lock" and clouding of the pool. Cyanuric acid level is lowered by draining part of the water out of the pool and diluting the remaining water with fresh water. Generally cyanuric acid level should be kept below 60 ppm. Stabilized forms of chlorine should not be used for superchlorination because cyanuric acid level may be increased. "

[Watermom]

SJohnson wrote:
"Cyanuric acid dissolves very slowly and is best predissolved in warm water before introducing into the pool. If it is not predissolved it may take several days to dissolve completely."

I have not found this to be true. CYA will not just dissolve quickly even in warm water. It will still take awhile. Don't worry about it. Just pour it in through the skimmer while the pump is running. Then, don't test for it, backwash or add more for about a week to be sure you give it time for all of it to dissolve. It is better to add it gradually and sneak up on your target rather than try and hit it in one dose. Be patient and you can get the level where you want it to be.

Watermom

[SJohnson]

That's in the quote from the "WATER CHEMISTRY FOR SWIMMING POOLS". I actually have always used the panty hose method, and have never tried dissolving it in warm water . . .

SJohnson

[waterbear]

(OTO... is this a FC or TC measurement?) and 3 PPM is the max the kit'll measure (recommended is 1.0~1.5) Does Ben's kit measure beyond 3 PPMs?

I do have to say I'm a bit nervous... I've had iron staining problems and with high FC, I'm afraid that the iron will be forced out of the water onto the liner. Man I have to get that iron out of the pool!

OTO measues total chlorine. Some people say that if you read the test withing 15 seconds you can get a free chlorine reading and then let it sit for about 2 minutes to get your total chlorine reading but it is a rough guide at best. If the color gets darker upon standing you most likely have combined chlorine but I would not trust it to tell you the amount.
Ben's kit has both OTO and FAS-DPD titration tests. The OTO test is good for a quick check on your levels(and Ben's wil measure to 5 ppm I believe) which in theory should be done daily and the FAS-DPD test will be able to test levels up to, I believe 50 ppm free and combined chlorine with an accuracy of either .2 or .5 ppm and would be your weekly test or your test when there are problems.
Bad news about the iron, unless your pool water is replaced or you filter all the pool water with an iron removing resin it will stay in your pool. When conditions are right(wrong?) it will deposit in your pool as a stain. When you put in a metal treatment it will dissolve back into the water. Nothing wrong with adding metal treatment when needed. If you are very lucky , when it deposits out of the water it will do it in your filter medium and not in the pool and it can then be removed by changing the filter medium. Works out well if you use DE, pretty costly if you use a cartridge.