Trichlor tablet alternatives?

[grannie14]

Topic split off by Moderator

We had a beautiful pool all this summer after two horrible years of fighting algae and spending hundreds $ on liquid chlorine. About this time last year, we purchased your special testing kit and because CYA was high, drained 1/2 of our pool and started over. Followed your shocking instructions and in a couple days had beautiful water. We installed an automatic chlorinator and used 3" Trichlor tabs and didn't even have to shock all summer. Just added an occasional 1/2 gal of liquid when the grandkids were in for long days. We get a lot of evaporation and even with the solar cover have to add water almost every day in summer. Added "Metal Out" occasionally because our well water has iron.

Last week our pool turned dark green with algae in a matter of a couple days when we were out of town. Tested and found CYA at 100!!! Had no idea until I started looking here that Trichlor raises CYA so bad. So guess we have to drain 1/2 again......drat!

So my question is, is there a non-trichlor or non-dichlor tablet product I can use? We just love the convenience of the tablet feeder but sure don't want to drain the pool every year. Any suggestions?
Stats: 21,000 gal fibreglass pool, sand filter with new synthetic sand (forgot the name), Pentair 2-speed pump.

 

[chem geek]

Re: CYA Buildup: What Level?

(deleted post meant for josephny in another thread)

 

[PaulR]

Because convenience matters to you a great deal, perhaps you should look into a salt-water system. You load up the pool with salt, then the SWG unit generates chlorine. From what I can tell, once you have it set up it mostly takes care of itself; certainly doesn't require daily fussing.
--paulr

 

[chem geek]

Re: CYA Buildup: What Level?

grannie14,

Welcome to TFP!

You have discovered the unfortunate conundrum of pool maintenance -- namely that the most convenient form of slow-dissolving chlorine has the side effect of increasing the CYA level requiring other steps to prevent algae growth. There are several options.

• Use unstabilized chlorine as your primary source, specifically chlorinating liquid or bleach. This usually requires more frequent addition, usually every day or two unless you use a pool cover opaque to the UV rays of sunlight in which case you can usually add chlorine twice a week. This is what most people on this forum do (unless they have an SWG). Some pool services use high CYA levels (80-100 ppm) and add chlorine once a week with large swings in FC (4-14 ppm).[/*:m:2mja12g8]
• Use a saltwater chlorine generator (SWG) system. There are some increased risks of corrosion or stone degradation that can be mitigated.[/*:m:2mja12g8]
• Use an automated chlorine dosing system such as The Liquidator (see this thread and this thread) or a peristaltic pump.[/*:m:2mja12g8]
• Use Trichlor pucks/tabs in an inline chlorinator or floating feeder, but regularly dilute the water significantly to keep the CYA in check. This can work in smaller pools with sand filters that get backwashed weekly and where there are regular rains that overflow the pool to dilute the water. Otherwise, intentional partial drain/refill on a regular basis is needed.[/*:m:2mja12g8]
• Use Trichor pucks/tabs and use a weekly PolyQuat 60 algaecide (at extra cost). This may let you get to perhaps 150-200 ppm CYA with around 3 ppm FC before you start running into problems.[/*:m:2mja12g8]

There are other methods for preventing algae, but they have problems. Linear quats can foam, phosphate removers can cloud, and copper-based algaecides can stain. 50 ppm Borates are OK (though dogs should not drink from the pool regularly) though are mild so are more like insurance with some algae inhibition.

You may note that those not using Trichlor on this forum hardly ever shock their pools. Weekly shocking is just a way of increasing the FC high enough to temporarily make up for the fact that there is too much CYA in the water such that the FC/CYA ratio is too low and algae can slowly grow. With continued use of Trichlor with CYA buildup, even weekly shocking isn't enough at some point.

Richard

 

[frustratedpoolmom]

Re: CYA Buildup: What Level?

(deleted post meant for josephny in another thread)

Sorry Richard for the confusion, I thought you were responding to her...

 

[AnnaK]

I use a combination of trichlor tables in an automatic feeder and liquid chlorine at probably 10% and the only time I 'shock' my pool is when I open and when I close.

My feeder is an inline Hayward which takes 3" trichlor pucks, 7 of them at a time. I have it set to somewhere between 1/8 and 1/4 on the little dial. I start the year at 0 CYA and end it with between 40 and 50 CYA. Our season runs from late May to the end of October and I don't know what happens to the CYA between October and May. Our pool is not covered in winter.

With the slow feed of CYA I still add a small amount of liquid chlorine twice a week, about 4 cups each time, and in general my FC level is at 5 ppm. The trichlor seems to add about 2 ppm per 24 hour period. Our CYA stays controlled because we have a lot of splashout and refill approximately 2 inches twice a week.

The pint being, you can use a combination of trichlor and bleach without overdosing on CYA and the convenience of trichlor during an absence is really nice.