Cyanurites will penetrate the walls and keep leaching into the water. That would explain your levels rising. you can cut out the tablets for awhile which are the source.

Your CYA is going up due to the use of the pucks, which are chlorine stabilized with CYA. Each puck you use adds CYA to your water. I can't remember the rate off the top of my head, but it will go up quickly if all you are using are pucks to chlorinate. You could switch to liquid chlorine and abandon the pucks altogether. That leaves you with having to manually add liquid chlorine every couple of days, but that is what I do. You can also purchase a liquid chlorine dispenser to make adding liquid chlorine a little more automatic.

My pool builder is going to be having me use theTrichlor pucks after the pool is finished. What is the deal with those? Some people seem to use them and not ever have problems with CYA, but lots of people seem to develop very high CYA levels with them. After reading how hard it is to get rid of CYA I am nervous about using these pucks. The idea of them seems nice and easy.......sanitizer and stabilizer in one convenient tablet. I'm starting to think I would be better off just using bleech and then CYA as I need it to keep levels optimal.

Kurt

Well, as the others said the tri-chlor pucks will slowly increase your CYA levels over time until they get excessively high. This is worse in some areas of the country, especially if you don't get a lot of rainfall (which tends to water down the CYA levels). Once the CYA level gets too high, unfortunately the only way to lower it is a water swap. The percentage of water depends on how high the CYA level is. You may want to read up on the BBB method of chlorination, see link below. Once you get the CYA level down you can start BBB and the CYA should stay under control. A lot of people swear by it.

Kurt, you want to start the pool up as suggested by the PB. When using tri-chlor pucks it typically takes years for the CYA levels to become a problem, so it's best to let the PB start you up and don't try BBB (or any other methods) until the chemistry is stable.

Here is a link that might be useful: BBB method

Generally all people who use pucks will eventually have a problem with excessively high CYA levels, they just may not realize it. I used pucks for many years before I became educated on BBB and never even tested my CYA. Rain and oversplash do help keep it down but eventually it'll get up there and then the pool will be much more difficult to maintain. Once your CYA reached 30-50 you should probably ditch the pucks and consider a different chlorination method. Bleach is very cheap and affordable. It's main deterrent is that you have to remember to add it on almost a daily basis. But an automatic dispenser can assist easily with this problem. A year ago I purchased a "Liquadator" which is basically a large bucket that sits in-line with your filter and delivers measured bleach or chlorine to your pool. Very cheap and very effective. I would highly recommend it to any one looking for an affordable and reliable way to deliver Chlorine.

Thanks trew and keithw for your help.........what can I expect for the first few months after I start up my pool using the Tri-Chlor pucks? I mean if normal CYA is 30-50 and if it takes a long time to see those levels get too high, then I would think that using the pucks it would take a long time to see it get up to the normal 30-50. Using the pucks from the outset will I see normal CYA levels or are the pucks administerd at such a rate that you are simply continually fortifying the Chlorine level at a rate that you are not relying on the CYA to "hold" on to the chlorine. By the way I am in Seattle so it is not a dry climate.....lots of rain and clouds even in summer.

Kurt

Tri-Chlor and Di-Chlor tabs are both acidic in nature and will cause your PH to rise. Of course this can be offset by adding acid. In addition for every 10ppm of chlorine added Tri-Chlor will also add about 6ppm of CYA and Di-Chlor will add 9ppm of CYA so you can see that your CYA will rise quickly is these are your only sources of chlorine.

An alternative to the above is Cal-hypo which does not add CYA but does have the disadvatage of adding about 7ppm of calcium for every 10ppm of chlorine.

Liquid chlorine or bleach are not acidic and do not add any other accumulating chemicals.

I use bleach and so do many others, but the chose is yours and there are pros and cons to each of the methods above and other methods that I did not mention here. Understanding how each impacts your pool is the key. It's a little daunting at first, but some basic understanding of your pools chemistry will save to $$$ and frustration down the road and will allow you enjoy your investment much more.

Riles

* Posted by riles_j (My Page) on
Thu, Feb 28, 08 at 14:15

Tri-Chlor and Di-Chlor tabs are both acidic in nature and will cause your PH to rise. Here is the Actual
Tri-chlor is about 2.9 ph di-chlor 6.9ph 7 is neutral.

Thanks for your responses. I think I will start off with what my PB has set up, the Trichlor pucks. Thanks to this forum I am aware of how CYA can climb if you don't pay attention and I will keep an eye on it and PH with carefull monitoring. When I get to that point I will have had some experience in balancing the chemicals in my pool and then, maybe, begin to try the BBB method.

Kurt

Good luck Kurt.

One edit, for my above response. I mentioned that Tri-Chlor and Di-Chlor are both acidic in nature and will cause your PH to rise. Not sure what I was thinking there, but acid causes the PH to drop not rise. They are both acidic in nature and as poolexpert pointed out Di-chlor is less acidic than Tri-Chlor, but both will have the net effect on lowereing your Ph over time.

As you can see I get this stuff mixed up all the time myself. Good luck and I'm sure this will be second nature in short order.

Riles

On a plaster pool you are better off using an acid based chlorine, if you do not want to need to add massive ammounts of acid to control the pH.

The pH of the surface is very high, so the pH on a plaster pool tends to drift up on a regular basis.

Thanks everyone

"Liquid chlorine or bleach do not add any other accumulating chemicals." Do they not add salt?

I know this is an old thread, but.......
Our pool was just built and I'm trying to figure out chemicals. I've been reading at tfp and didn't understand much of stuff I read about cya. This thread answered many of my questions. Thanks