Well-known member
May 17, 2016
Mendon MA
This forum has been a great place for me as I have learned a lot and saved a lot of money! On that note I want to share a recent success story.

This year I had to replace my inground pool liner. I live on a lake and I have previously filled my pool with lake water. In years previous I have had no issues balancing the lake water. This year was completely different. The water was an off yellow color prior to adding any chems. I had no issues balancing the buffer, PH and CYA (baking soda/borax/CYA). Once I added the chlorine to SLAM the pool the water turned from an off yellow to straight black. I got my FC up to 25 and after a day of filtering the water color did not improve. At that point I turned to TFP and Google and made the assumption that I had metal in the water. I found a lot of homemade filtering devices for above ground pools but not very much info for ingrounds. I decided to improvise and steal solutions from numerous sources. My overall goal was not to add a sequestrant, instead I wanted to lower the metal levels.

I started by opening up a pillow and adding the stuffing to the filter basket. I stuffed enough material to densely fill the basket. I then ordered 32 oz of polyfill from amazon for $10 (https://www.amazon.com/gp/product/B004ALQ0M2/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1)

I next grabbed some tube socks and doubled them up. I zip tied a set of socks to each of the returns to the pool. Considering I didn't have a bunch of socks to spare I ordered a 12 pack of socks from amazon for $10 (Amazon.com: Hanes Boys' Medium - Shoe Size: 9-2.5 Durable Cushioned and Reinforced Heel and Toe Crew Socks, 12 and 24-Pack Available, White-12 Pack: Clothing)

I set the VSP pump to 2000rpm which is a medium speed for my pool. I saw a difference within 24 hours. The water went from black to dark brown. Each day I changed out the socks/filter media and backflushed my sand filter. The socks and poly filling went from white to dark red. The FC level remained high for the next couple days as the SLAM worked.

At this point I thought the water was filled with iron so I bought the water to the pool store for testing as my Taylor kit does not test for metals. The pool store informed me I had a high copper level and tired to sell me numerous sequestrants. I told them I was going to continue filtering, they wished me good luck.

After a week the water was cleaning up nicely expect for the deep end. I ended up hooking up my vacuum and letting the pump pull water from the bottom of the deep end instead of the top. I am assuming the copper water is heavier and with the socks on the jets the water circulation was not maximized. After an additional 2 days the water was clear.

Each day I changed the socks and poly fill. Overall I went through 16 pairs of socks, 2 pillows, and a bag of poly fill. Each time these would be changed they would be dark red colored and weighed a ton.

I brought my water back to the pool store and was able to get my copper level to <.2ppm. I am going to continue using the polyfil until I run out of material, it is use it or trash it as I have no other outlets for this material.

Hopefully this info will help others. I do not know what my intial copper level was when I started and I was lucky not to get any staining on a brand new liner. If you have any questions feel free to reach out.


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TFP Expert
Platinum Supporter
May 23, 2015
Tucson, AZ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
It looks more like iron to me. It would be highly unusual to find copper in fresh lake water unless the lake was man made and someone added copper to kill off an algae bloom. Iron can easily look like a reddish brown color. To test, take some of the discolored poly fill and soak it in a solution of fresh bottled water and vitamin C tablets. If the color fades then it’s iron. If the color remains or gets darker, it’s copper.

I don’t particularly trust metal testing at pool stores as they are generally not careful about testing. Also, once a metal precipitates out of the water and forms a colored compound, it is no longer in solution and will not register on a metal test unless careful steps are taken to redissolve the metal.
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Gold Supporter
Silver Supporter
Jun 2, 2020
Pool Size
Liquid Chlorine
Hi! This is fantastic. Dumb question, since my pool is still being built, how do you zip tie to the returns? Do you have a closer pic? Pool looks great! ❤️
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