Removing antifreeze from return lines

Scottman

Active member
Mar 4, 2015
34
Iowa
#1
I remember researching this last year when I was going to open my pool and didn't find an easy answer. I would like to share what I did this year and if its already been posted somewhere I apologize. We all know its easy to stick a shop vac hose in down the skimmer hole because the water level is below that but my returns are always under water and have 1 1/2 inch screw in plugs with O rings. I rigged up a 1 1/2 inch PVC male threaded piece with a reducer with a threaded female piece, then a male threaded 90 degree 1" nipple and a 6 foot 1" rubber hose. After I put these pieces together I needed a temporary plug for the 1" nipple so I rigged one with a piece of pipe fitting wrapped in electrical tape anything will work. I then reached in the water and unscrewed the plug and quickly screwed in my PVC rig without the hose attached. Then I pulled out the plug and pushed the hose on the nipple. I handed the hose to my wife who held it over a pail and used the same method as blowing out the lines with that I used to winterize and emptied all 3 returns. It took about 13 gallons out which I overkill in the winter but it gets darn cold in Iowa!
 
Dec 2, 2012
14
#3
I have never worried about the anitfreeze. It just mixes in with the pool water and disappears.

I guess you could just blow it out from the skimmer and let it run out the pump end. It doesn't seem to cause any problems as far as I know.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
14,519
Tucson, AZ
#4
13 gallons of antifreeze is a lot of contaminant to add to a pool so good work in removing it. While the anti-freeze itself is not considered harmful, the reaction of antifreeze with chlorine is a bigger problem. Chlorine will react with antifreeze and form all sorts of chlorinated compounds (trihalomethanes or THMs) that are not good for you. One of them is chloroform and that doesn't show up on a CC test. So, without going to extreme lengths, it's always best to remove as much of the antifreeze as possible.
 

Scottman

Active member
Mar 4, 2015
34
Iowa
#5
Here is a picture of the PVC fitting I used to screw into the return line after removing the winter screw in plugs. As I mentioned above in this post I plugged the hole of the elbow while making the switch from winter plug to this fitting and then quickly removed the plug and pushed on the 6 foot hose. The plug probably wasn't necessary as the water wanted to enter the return line instead of the antifreeze wanting to flow out in the pool so what I'm saying is when switching the plug for the fitting water is trying to flow into the return so no antifreeze is going into the pool at this time so the longer it takes you to get it threaded and the hose put on the more pool water that went into your return lines and mixed with the antifreeze you will have to pump out. As I stated I did them one at a time and just like blowing them out in the fall except I am capturing the liquid being expelled out of the return. The process was very simple and didn't take a lot of time. Two main reasons I did it were that my 3 year old grandson and his 1 year old little brother will be spending more and more time in it as they get older and I don't like the thought of them drinking more chemicals than they need to, second after battling algae problems after opening my pool the last two years since I built it I researched and found that it takes a lot of chlorine to "eat up" all of that antifreeze and I must admit after 5 days of opening, my pool is still crystal clear.
 

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Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
#6
Here is a picture of the PVC fitting I used to screw into the return line after removing the winter screw in plugs. As I mentioned above in this post I plugged the hole of the elbow while making the switch from winter plug to this fitting and then quickly removed the plug and pushed on the 6 foot hose. The plug probably wasn't necessary as the water wanted to enter the return line instead of the antifreeze wanting to flow out in the pool so what I'm saying is when switching the plug for the fitting water is trying to flow into the return so no antifreeze is going into the pool at this time so the longer it takes you to get it threaded and the hose put on the more pool water that went into your return lines and mixed with the antifreeze you will have to pump out. As I stated I did them one at a time and just like blowing them out in the fall except I am capturing the liquid being expelled out of the return. The process was very simple and didn't take a lot of time. Two main reasons I did it were that my 3 year old grandson and his 1 year old little brother will be spending more and more time in it as they get older and I don't like the thought of them drinking more chemicals than they need to, second after battling algae problems after opening my pool the last two years since I built it I researched and found that it takes a lot of chlorine to "eat up" all of that antifreeze and I must admit after 5 days of opening, my pool is still crystal clear.
That is a really great idea. Thanks for sharing. :goodpost:
 

run53

LifeTime Supporter
May 4, 2010
347
#7
I want to build one of these, but I'm having trouble understanding your parts list. Is it possible to show each part separately? Or better yet a parts list I can search for on-line :)

I think I see:

1) 1 1/2 threaded PVC male on one side, female on the other
2) male threaded reducer?????? - not sure about this piece
3) male threaded (size??) 90 degree with 1" nipple
 

PoolguyinCT

In The Industry
Jul 21, 2014
2,718
Connecticut
#8
13 gallons of antifreeze is a lot of contaminant to add to a pool so good work in removing it. While the anti-freeze itself is not considered harmful, the reaction of antifreeze with chlorine is a bigger problem. Chlorine will react with antifreeze and form all sorts of chlorinated compounds (trihalomethanes or THMs) that are not good for you. One of them is chloroform and that doesn't show up on a CC test. So, without going to extreme lengths, it's always best to remove as much of the antifreeze as possible.
13 gallons?? I have done water park features with less than that & these are 10” & 12” systems.
 

Scottman

Active member
Mar 4, 2015
34
Iowa
#9
I want to build one of these, but I'm having trouble understanding your parts list. Is it possible to show each part separately? Or better yet a parts list I can search for on-line :)

I think I see:

1) 1 1/2 threaded PVC male on one side, female on the other
2) male threaded reducer?????? - not sure about this piece
3) male threaded (size??) 90 degree with 1" nipple
1) The 1 1/2 inch piece is threaded and allows 1 1/2 inch PVC pipe.
2) The reducer is 1 1/2 glue in on one end and I believe 1 inch female to accept the elbow
3) The male elbow is 1 inch threaded

If at all possible, do what I did and go to the local hardware store a mile down the road and just put parts together until it works! LOL!

- - - Updated - - -

13 gallons?? I have done water park features with less than that & these are 10” & 12” systems.
I know its a little overkill but with temps at -25 in the winter and my lines covered with concrete and rebar that I poured myself I get a little paranoid :)
 
Jul 8, 2017
1
Roanoke, VA
#11
This is the first year for our pool, so maybe I am missing something? I just opened the basket on the pump end, opened only one line at a time, uncapped the other end, and used the shop vac. to suck all the antifreeze out (just stuck the hose over the hole in the basket. I sucked about 15 gallons through each line. The first 5 gallons was mostly antifreeze, the next 5 gallons was weak antifreeze. The last 5 gallons was clear water. FWIW, my shop vac would not push the water back to the pump, I had to go to the pump end and suck the water through the lines. I guess the shop vac is more efficient in that direction. My water was up over the skimmers, maybe that makes a difference?
 

Pool_Medic

Well-known member
Apr 1, 2018
436
Bangor Maine
#12
If you get a cyclone you will need half a gallon to winterize. It’s blows all lines clear of water and the 1/2 gallon can be poured in the skimmer body. I live in Maine and we get severe freezes. 13 gallons isn’t over kill, its foolhardy.