Trichloro versus Dichloro

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T

TJTJ

0
Oct 18, 2015
62
Orinda, California
I have 3" pucks where Trichloro -s-triazinntrione is the active ingredient 94.05%
Also been using Sodium Dichloro-s-triazinetrione-Dihydrate is the active ingredient 99%
The latter is the granular chlorine I have been using. I believe the 3" pucks have been increasing the pools CYA.
Is the granular chlorine also? I have been using the pucks for about a year. Just a month as to the chlorine.
CYA has increased to 125 from 100. Just ordered a TF-100 test kit to be positive of the readings. The CYA
readings came from the pool store.
 
Welcome to the forum, & congrats on taking your first step to a Trouble Free Pool by ordering a proper test kit.

You are correct, both Trichlor & Dichlor will also raise CYA. With every 10ppm of Free Chlorine added with Trichlor, you will also add about 6ppm of CYA, with Dichlor it is worse, for every 10ppm of FC added you will increase your CYA about 9ppm.

It would be best for you to stop using Stabilized Chlorine as to not add any more CYA until you can properly test.

Here at TFP we recommend liquid chlorine, aka bleach.

Have a read here:

The ABC's of Pool Water Chemistry

How to Chlorinate you Pool

Recommended Chemicals

Please don't hesitate with any questions you may have.

Dom
 
Thanks Dom and Pabeader -- I purchased some HDX Germicidal bleach. (home depot) The 3.78 quart container says it yields 7.86% available chlorine. My question is how much should I add every week? Or twice a week? I have a pool with approximately 28,000 gallons, in ground. I realize it will be trial and error to some degree. Maybe a good starting point of how much to add? Thank you in advance. TJTJ
 
TJTJ said:
Thanks Dom and Pabeader -- I purchased some HDX Germicidal bleach. (home depot) The 3.78 quart container says it yields 7.86% available chlorine. My question is how much should I add every week? Or twice a week? I have a pool with approximately 28,000 gallons, in ground. I realize it will be trial and error to some degree. Maybe a good starting point of how much to add? Thank you in advance. TJTJ
Click to expand...
That should be 8.25% sodium hypochlorite. Does the bottle list the ingredients?

Also, be sure to check the date code, chlorine loses its strength over time.

Chlorine date code decoder

You should be adding chlorine daily to maintain the proper ratio of FC to CYA. If your CYA is indeed 125ppm, the MINIMUM your FC should ever be is 9.5ppm, with your daily target around 14-15ppm.

How much chlorine your pool uses daily is dependent on the conditions in your pool, the amount of sunlight on the pool, water temp, bather load, etc. Everyone's pool is different.

FC loss is a percentage of the FC in the pool.

In the height of the season when my pool is it's warmest, the kids are home from school & and we are using it daily, I find that with a CYA of 40ppm, and maintaining a target FC around 8ppm, I lose about 3ppm daily, or about 35% of my FC.

With that logic, if you are maintaining a target FC of 15ppm, expect to use about 5ppm of FC daily. In a 28000 gallon pool that will be just over 1-1/2 gallons (207oz) of 8.25% bleach daily.

Let's hope that the Pool $tore has erred on the high side with your CYA level, but unfortunately it is usually the opposite.

Dom
 
The FC loss is only roughly proportional to the FC level AT A CONSTANT CYA LEVEL. At higher CYA levels there is more protection from the UV in sunlight so that at the same FC/CYA ratio the ABSOLUTE FC loss from sunlight is actually a little lower. So maintaining a 7.5% FC/CYA ratio, while you may lose 3 ppm FC at 40 ppm CYA, you'd likely lose less, perhaps only 2 ppm FC, at 80 ppm CYA. See this post that shows this effect at SWCG levels (5% FC/CYA ratio) but the effect is the same at regular non-SWCG pool levels.

Basically, at high CYA levels but a normal FC/CYA ratio the absolute loss of chlorine is lower and operating costs are lower. This is why higher CYA levels are recommended for SWCG pools because they are usually undersized and minimizing chlorine loss and therefore required generation minimizes the negative side effects of pH rise associated with such chlorine generation.
 
chem geek said:
The FC loss is only roughly proportional to the FC level AT A CONSTANT CYA LEVEL. At higher CYA levels there is more protection from the UV in sunlight so that at the same FC/CYA ratio the ABSOLUTE FC loss from sunlight is actually a little lower. So maintaining a 7.5% FC/CYA ratio, while you may lose 3 ppm FC at 40 ppm CYA, you'd likely lose less, perhaps only 2 ppm FC, at 80 ppm CYA. See this post that shows this effect at SWCG levels (5% FC/CYA ratio) but the effect is the same at regular non-SWCG pool levels.

Basically, at high CYA levels but a normal FC/CYA ratio the absolute loss of chlorine is lower and operating costs are lower. This is why higher CYA levels are recommended for SWCG pools because they are usually undersized and minimizing chlorine loss and therefore required generation minimizes the negative side effects of pH rise associated with such chlorine generation.
Click to expand...

Thanks to the forum:) I have not received my tf-100 test kit yet, but it is on the way. I had way too much algae this summer and the pool store said the high phosphates was the issue. I spent major $$ on stuff to get rid of phosphates, but I still had algae. I did some research and found this site:))) I believe the algae is because of high CYA, while free chlorine is within range. Pool store tests show 2, with a range of 1-4. CYA shows 125. I will test myself hopefully by the beginning of next week. I had too brush the pool every day in the summer. Was the first year ever. The fellow at the pool store said I needed to add trichlor, 3" pucks. I did and it upped my CYA, hence the came with algae. The free chlorine stayed at 2 though. Oh Brother. Thanks for all the help.
 
one more thought. The pool looks good now and did during the recent warmer months. My guess is that if the pool was not brushed this would not have been the case. In previous years I did very little work. (brushing)
I believe I have to lower the CYA and maintain the proper CYA/FC ratio. I learned how to lower the CYA via another post in the algae part of the forum. Forget the exact name:(
 
TJTJ said:
one more thought. The pool looks good now and did during the recent warmer months. My guess is that if the pool was not brushed this would not have been the case. In previous years I did very little work. (brushing)
I believe I have to lower the CYA and maintain the proper CYA/FC ratio. I learned how to lower the CYA via another post in the algae part of the forum. Forget the exact name:(
Click to expand...
If you are referring to "Bio-Active" I would not recommend it. I don't think anyone here at TFP who tried it has been successful.

The best proven method is water exchange. Use your pool water for irrigation, the use your irrigation water for the pool.

Dom
 

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-- I purchased some HDX Germicidal bleach. (home depot) The 3.78 quart container says it yields 7.86% available chlorine. My question is how much should I add every week? Or twice a week? I have a pool with approximately 28,000 gallons, in ground. I realize it will be trial and error to some degree. Maybe a good starting point of how much to add? Thank you in advance. TJTJ
Click to expand...

Hopefully the HDX bleach was sitting inside the store and not outside. Also, please check the date on the container as bleach degrades over time and if this was outside, the process is a lot faster. Please go to Pool Math and plug in all the numbers and the calculator will tell you what to add.

http://www.troublefreepool.com/calc.html
 
TJTJ said:
Dom - I checked the active ingredient, ur correct, 8.25% sodium hypochlorite. Now I just have to determine date. much trickier. 15 252 07:26 G 122 CA-02 L1 how it reads.
Click to expand...

Refer to the link I posted in post #6 of this thread.

As mentioned it is the 252nd day of 2015, or Sept. 9, 2015

Dom
 
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