I'd like to add some Polyquat to my pool as added insurance since I have an older mesh cover that lets sunlight and rain into my pool and we often get warm days occasionally in late fall and early winter. According to the pool professional who is closing my pool, FC needs to be at 5 or below when the Polyquat is added or it won't work as effectively. He told me to shock the pool to a FC level of 10 three days before closing and add the Polyquat the day before when FC goes down to 5, and let the pump run for 24 hours afterwards. According to the closing section on Pool School, I need to get my FC up to shock level which is 20 and add the Polyquat once it goes down to half that, which is 10. I've read that Polyquat oxidizes chlorine at high levels but does it make the algeacide ineffective if it is added when the chlorine level is 10 when it is added? If it just lowers the chlorine level and doesn't effect the effectiveness of the algecide, could the FC be increased some before closing if it lowers FC down too much?
FC level when adding polyquat
- Thread starter al27
- Start date
- May 23, 2015
- 24,472
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Polyquat gets oxidized by chlorine, not the other way around. Even when it gets oxidized, the byproducts still have some biocidal activity. Waiting until the FC is below 10ppm is what TFP recommends based on the available information.
How much below 10 ppm does the FC need to be when polyquat is added to prevent the polyquat from getting oxidized by the chlorine? Does the pump need to run 24 hours after it is added like my pool professional recommends?
There is no magic number, and I doubt anyone has ever produced scientific evidence of any differences. As Matt mentioned, this is a great starting point. This really does not matter. I have tested chlorine prior to the Poly60, and right after the Poly60 (almost immediately after pump shut off), and the chlorine is consumed, almost cut by 50% at around these levels. Although, I can not test for Poly60. If in doubt, allow your levels to remain at the CYA/FC ratio for your pool and then add the Poly60. Allow to mix for at least 12 hours - 24 hours, close the pool and enjoy the winter.
Are you suggesting that I should add the Poly60 once FC lowers to target level for my CYA which is 6-8 ppm? If the Poly60 cuts the chlorine in half, is there any harm in bumping it up to 8 ppm right before closing since that where I normally keep my FC level? It makes me a bit nervous to close with a really low FC level since we sometimes get warm days in November. Last year, we had a week of warm weather in November and my pool was a swamp when we opened, even though we closed with a FC level of 15 and closed late and opened early. I thought I’d try the Poly60 this year, in case we get warm weather like this again and see if it makes a difference.
My statement on the chlorine in half is based on my experience only once and should not be viewed as scientific evidence. There is no difference between 10 ppm or 8-10 ppm. Stating that you close your pool late and open early needs to be clarified. When exactly did you close, and when exactly did you open? What was the water temperature? The cover plays a vital role in the closing process as well. A solid tarp is huge vs. a lesser expensive type of mesh cover. There are really high end mesh covers as well that do very well.
I have closed my pool from Mid September to Mid October the same way and have never opened up to a green pool (pool cleared up in less than 3 hours (from being dirty, not full of algae), but is never opened any later than last week of April.
Please advise water temperature, date closed, date opened, and what type of cover.
I have closed my pool from Mid September to Mid October the same way and have never opened up to a green pool (pool cleared up in less than 3 hours (from being dirty, not full of algae), but is never opened any later than last week of April.
Please advise water temperature, date closed, date opened, and what type of cover.
I’ve got a mesh loop loc cover and last year we closed a few days before Halloween when water temperature was around 58 degrees and opened the first week of May. We had a few 70-80 days in November and March and a mild winter so that might have contributed to the severe algae bloom that we had. I thought I’d try the Poly60 this year and see if it makes a difference in case we get warm weather like this again but it makes me nervous to close with a low chlorine level if the Poly60 lowers it below target level. Just wanted to know if I should bump the chlorine back up to target level (8) if it cuts chlorine down below target level or just leave it low.
You can try bumping up your levels, then using the Poly60. Put in 3/4 of the quart, mix properly for at least 12-24 hours. Considering you have a pool of my size, you may consider purchasing a solid tarp to place over your mesh until it gets real cold. My guess is that your mesh cover allows to much sunlight in. Instead of purchasing a larger tarp (which would be easier and they are stronger) at around $80-$100, you may wish to purchase inexpensive blue covers at Wal-Mart. Cover at least 80% of the pool, secure with ties as this will allow water to drain and block out most of the sun.
You definitely are following protocol. The issue last year was those sunny warm days in November. I remember we had such nice weather. Good luck and keep us posted!
You definitely are following protocol. The issue last year was those sunny warm days in November. I remember we had such nice weather. Good luck and keep us posted!