Stabilizer, CYA, Conditioner...why do I need it?

Do I really need Stabilizer?

sun

Seriously, nearly everytime I am explaining pool

water chemistry and I get to the point about cyanuric acid, I see my customer's eyes lose focus and I know that I have lost them.  Too much information has just blurted out of my mouth, and I know they will forget what I have told them. 

"The important thing to remember is

chlorine and keeping my pH in balance, right?" they inquire hopefully, thinkikng that their pleadings will make their pool water not need so much attention. 

"You need stabilizer too." I remind them, and then go on to explain how an outdoor pool (especially in the St. George desert heat) needs the proper amount of cyanuric acid (A.K.A. stabilizer or conditioner) to help keep the chlorine from evaporating.  If they don't put enough in they will keep having to put in a ton of chorine because it won't stay 'stabilized' in the pool. 

But, where does the chlorine go?  What is happening to it? If 20 parts per million are good, why don't I want to put in more so that my chlorine will last even longer?  Well, if you have ever had any curiosity about CYA, stabilizer or conditioner, here is the rundown on why having the 'right' amount is really important for your pool, and why too much of it is a bad thing.

What is it?

"Cyanuric acid is a weak acid that is marketed as a chlorine “stabilizer” for swimming pools.  Other terms used by the pool supply industry are “isocyanurates”, “conditioner” or “CYA”.  When exposed to the ultraviolet klor tablettarays of the sun, the free chlorine in the pool water will break down and escape.  Cyanuric acid is intended to reduce this loss of chlorine." (Pennsylvania Department of Health) In our store, the brand we sell calls the cyanuric acid "water conditioner."  Having a few names is confusing for customers, and I think that this is one of the reasons people either don't know that they need it or are confused about it.  Another reason pool owners seem to be confused about cyanuric acid is that it is a product that you don't have to put in very often because it doesn't leave the pool water unless you drain it or have splash out and put in fresh water.  Because of this, people tend to forget about it.

How do I get it in the pool?

At Tropical Pools and Spas we recommend that you check your cyanuric acid levels regularly for a few reasons.  1) Chlorine, in the form of dichlor and trichlor, are also known as isocyanurates.  They both contain cyanuric acid, so everytime you add shock with dichlor or tablets with trichlor, you are adding cyanuric acid (CYA) to your pool.  But, since this level is usually not quite enough to start a pool out, "Water Conditioner" is cyanuric acid sold in granular form that a pool owner adds to a pool, usually only at the beginning of the swimming season, or when they have added a lot of fresh water. A three inch tablet of trichlor has about 2 ppm of CYA and a 1 lb. bag of shock (dichlor) has about 1.5 ppm of CYA. 

Can you get too much? My Pool store is telling me to drain my pool!

Unfortunately, you can get to much CYA in your swimming pool, and this is something I try to warn customers about from the beginning (which is usually when they are too new to having a pool and they have just been bombarded with too much chemistry information). How does this happen and what can you do about it?  Well, it happens in a few different ways...

  1. Putting too much "Water Conditioner" in in the beginning.  This usually happens because someone puts it in without testing to see how much is in the pool before they put more in.  *Remember*, it doens't leave the water, and generally the only time you need to put it in is the beginning of the season or after a fresh fill. Pool owners with sand filters who can vacuum to waste or who backwash are putting in more fresh water than pool owners with cartridge filters, so they may need to put in more CYA than others.  Always, always, always, get your pool water analyzed at our store before you add more "Water Conditioner" to see what level  you are starting with.  Then, if the computer says to add 5 lbs, start with 3.5 and recheck, just to make sure you don't over do it.  It is much easier to slowly add it than to have to drain your pool. This leads to the second way it gets in your water and the reason you don't want to start out with a high number in the beginning of the season...
  2. Chlorine Tablets made of trichlor have CYA in them and add about 2 ppm (parts per million for those of you who don't speak 'pool water chemistry' yet) and every time you dissolve one to add chlorine you are adding more CyA.  Now, in some climates, maybe you don't go through so much chlorine, but we sure do here, in sunny St. George Utah, when we have week sof 100+ temperatures and the pool is filled with 10 kids for 8 hours a day.  That is a lot of chlorine to go through, and the levels of CYA go up pretty quickly.  Then, if you add shock (and you better add shock if you want your pool to look clean) you will add more CYA because shock is made from dichlor and it has about 1.5 ppm of CYA per pound.

I have too much, big deal?  I still don't see why I have to drain my pool!

The ironic thing about CYA... you need it so the UV rays from the blazing sun don't eat your chlorine up and leave you with an unsanitzed dirty, bacteria infested pool.  But, if you let the levels get too high, the CYA will reduce the overall effectiveness of the chlorine, making your pool unsanitized, dirty and bacteria infested...basically the thing your were trying to avoid when you added the CYA in the first place. So what is the right level?  How do you get the perfect amount with out getting too high?

  1. Buy slow dissolving chlorine tablets.  BE WARY OF CHEAP CHLORINE AT BIG BOX OR DISCOUNT STORES.  These tables look like they are a great price compared to what you can get them for at your local professional pool store, but there is a big difference.  The tablets that you get at a big box or discount store (not naming names :) disolve too fast and therefore are putting too much CYA into your pool too fast.  I see it every summer, customers coming in to get their water tested and can't believe that their CYA levels are so high, and the thing they usually have in common is that they bought cheap chlorine, thinking it would save them money.  In the end they have to spend more money to drain and refill their pool (not to mention the alkalinity problems it is causing...but that is a whole other article).
  2. If you know your levels are getting high, start to use liquid chlorine because it has no CYA in it.  Liquid chlorine is not as effective as other types of chlorine, but it will help you from getting your CYA too high and that is a good thing.
  3. Drain part of your water on a more regular basis, if you can.  Even a partial drain can help, because the fresh water will dilute the CYA.  Test your levels and when it waters to get on the high side, do a 1/4 or 1/3 drain. It isusually easier to dump a little wate than the entire amount.

chlor tablets

How much is too much?

Here are some general guidelines about CYA and the amount that you should have in your pool.

MAXIMUM LEVEL IS 100 PPM, at least according to many states. Health departments generally will not let county pools have more than 30 ppm.  Chlorine really loses its ability to sanitize when CYA is this high because all the CYA is bonding with the chlorine, and the time it takes to kill bacteria lengthens as the concentration of CYA increases. When CYA is too high you need to have a lot more chlorine in the pool to work, (and then you are probably putting in more CYA at the same time...a viscious cycle)

20-30 ppm is ideal for an outdoor pool that uses three inch chlorine tablets.

60-80 ppm for a salt system.  The reason you have more CYA with a salt pool is because you are not ever adding any extra CYA to your pool and need to start out with enough to keep the chlorine from evaporating. But, like I said before, checkCYA your levels of CYA before adding it.  (If you are not in a real hot climate, you can keep your levels lower too).

If you have over 150 ppm our professional testing equipment will not let the customer have their water analyzed and tell them they need to lower the CYA by draining.  Some customers don't want to drain and keep comming back wanting their water tested, but it gets tricky at that point.

Alkalinity

Alkalinity keeps your pH in balance.  When it is too high, pH tends to get locked, and when it is too low, pH tends to bounce all around (again, this a good topic for another article and too much to talk about here). CYA affects the pool's alkalinity levels quite a bit the higher it gets and unless the pool owner realizes what is going on, they can really get their alkalinity messed up.

In short, when CYA gets high, like

say a nice number of 120, you take 1/3 of that number and you remember it (40).  Now lets say you do an alkalinty test with your test drops and you get 12 drops for your blue reagent to turn yellow or red to turn green and you do your math calculations and figure out that your alkalinity is 120.  WEll, under normal circumstances this sounds like a great number for your alkalinity, but, your pH keeps bouncing all over the place and is really low.  So, you wonder what is up since alkalinity seems to be fine. 

Well, your alkalinity is not fine when yo

ur CYA is that high.  You must take 1/3 of your CYA and (do more math) subtract that from the alkalinity to get your adjusted alkalinity.  120-40 = 80, and for our recommendations, that is too low for your alkalinity and could explain your pH problems. 

Conclusion

You need CYA in your pool, but just not too much.  If you do get too much, you really are better off draining because you usually have to spend more money adjusting your alkalinty, and once the number is over 150 there is no real way to know how high it is so we are just guessing.