Tarp method in-place water replacement

JamesW

TFP Expert
Mar 2, 2011
19,794
Seemed to get stuck for the OP if you read through the whole thread. He used the word glues for like 10 minutes.
He got it loose pretty easily. All you have to do is get some water behind the tarp and it will come right out. Push the edges below the water and water will get behind the tarp as you begin to peel it loose.
 

duraleigh

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In The Industry
Apr 1, 2007
34,056
Sebring, Florida
water will get behind the tarp as you begin to peel it loose.
Of course....equalizes the pressure on both sides of the tarp.

Wow! The post has garnered a ton of replies in a very short period. Just an interesting idea, I guess.
 

JamesW

TFP Expert
Mar 2, 2011
19,794
Overall, I think that it’s a good reference for anyone who’s considering doing the tarp method. It shows the process pretty well as well as some precautions. Maybe a wiki article should be done.

Some important reminders:

1) Never secure the edges of the tarp in a way that could allow tension to build in the cover. The cover should always be floating loose and neutral in the water; it should never try to support the water on top in any way.

2) Be careful with a sump pump, especially on a vinyl liner. Beware of sharp edges or rust from old pumps.

3) Watch the process carefully.

4) Be aware of the potential risk to kids or pets that could fall in.

Do not do this if you are not sure that you can do it safely.

Do at your own risk.
 

mguzzy

Gold Supporter
Jul 8, 2015
2,041
OV, CA
Well done.. this should be a sticky/thread reference in the Wiki on this technique... The video is priceless.
Here is the full time-lapse of the entire process. Thank you all for your support over the years.
Now that is just the coolest thing!.... you could see when the pump started draining the deep end faster and the chair on the tarp starts to move as the tarp sucks in... I kept waiting for the part where you threw away your underwear.

For future, if anyone wants to duplicate this, and is concerned about the tarp getting stuck, here is a though that popped into my head.

Put something, maybe a 1 gallon plastic bucket under the tarp in the shallow end, near the steps/edge. This way if it ever gets stuck, you have a very accessible area where you can cut with a knife if you absolutely had to, and no worries about puncturing the liner underneath.

Or , put some sort of reinforced (so it wont collapse) hose under the tarp and leave exposed on the surface. If it gets stuck, you can hook up to a compressor or whatever to blow air under to break a seal.
I was thinking prepositioning a hose in the deep end to act like a pressure relief at the end of the process. When you are done draining (sucking) the water from below the tarp, you can then start filling the pool with freshwater under the tarp to break the seal.
 
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mguzzy

Gold Supporter
Jul 8, 2015
2,041
OV, CA
I dunno seems pretty straight forward to me:
1) get a big tarp, get a pump
2) put the tarp on the pool, hose on top
3) start the pump, start the hose
4) watch it on YouTube

My worry is that some yahoo will try this with his pool's pump, not pay attention and suck his pipes into his filter.
 
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AndyTN

Bronze Supporter
Mar 27, 2019
257
Memphis
I did this same method this Spring to do a water exchange right after AA treatment for iron. It was a lot of work but it actually worked out really well. Do not try this unless your tarp has a good 10 feet of extra width/length on all 4 sides. I had to shut off my pump periodically to allow my "surface water" from the hoses to catch back up. I also had to pull on the tarp to keep it firm without a bunch of crazy wrinkles. I had the hoses only in the shallow end to push the old water down to the deep end. When I could see the tarp getting near the main drains in the deep end, I shut off my pool pump and used the winter cover pump sitting down the sides to suck out the rest. I did not have any tears and I was able to get 99% of the water out without mixing.

I wish I had taken some pictures like you did but this method does work for a water exchange if your tarp is large enough and you have a lot of spare time to micro manage it all. As stated before, allowing the water to mix a bit and settling for 75-80% water exchange is probably more practical for most people.
 
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carlos31820

LifeTime Supporter
Nov 22, 2010
407
Midland, Georgia
I did this same method this Spring to do a water exchange right after AA treatment for iron. It was a lot of work but it actually worked out really well. Do not try this unless your tarp has a good 10 feet of extra width/length on all 4 sides. I had to shut off my pump periodically to allow my "surface water" from the hoses to catch back up. I also had to pull on the tarp to keep it firm without a bunch of crazy wrinkles. I had the hoses only in the shallow end to push the old water down to the deep end. When I could see the tarp getting near the main drains in the deep end, I shut off my pool pump and used the winter cover pump sitting down the sides to suck out the rest. I did not have any tears and I was able to get 99% of the water out without mixing.

I wish I had taken some pictures like you did but this method does work for a water exchange if your tarp is large enough and you have a lot of spare time to micro manage it all. As stated before, allowing the water to mix a bit and settling for 75-80% water exchange is probably more practical for most people.
So the question I have is, did this fix your iron stain problem? I keep thinking any day I’ll see those dreaded stains come back.

I think I have iron stain PTSD.
 

AndyTN

Bronze Supporter
Mar 27, 2019
257
Memphis
So the question I have is, did this fix your iron stain problem? I keep thinking any day I’ll see those dreaded stains come back.

I think I have iron stain PTSD.
The iron stains will come back and I do an AA treatment with water exchange every Spring. This was the first year I did the tarp for the water exchange so I would hope a 100% exchange would be improvements over previous years but my city water has iron in it. So good so far but I can see/notice very minor color on my fiberglass steps since I am paranoid but my wife can't tell. End of the Summer will be the big test. This year is also the first year I have kept polyfil in the skimmer continuously, changing it out once per week. I am also not using any metal sequestrant since I want the iron to precipitate on the polyfil.

The iron stains will come back so I am just doing all I can to mitigate them. I feel your pain and your experience of them returning is common.
 

carlos31820

LifeTime Supporter
Nov 22, 2010
407
Midland, Georgia
Ok. My city water does not appear to have iron in it as tested by me, tested by pool stores and tested by an independent lab I sent water samples to.

My next door neighbor has a liner pool as well and he’s never had the iron stains like I do and we’re obviously on the same city water. His pool is close to 10 years old.

It’s only been a week since I replaced the water so it’s way too early to tell.
 

mguzzy

Gold Supporter
Jul 8, 2015
2,041
OV, CA
Ok. My city water does not appear to have iron in it as tested by me, tested by pool stores and tested by an independent lab I sent water samples to.

My next door neighbor has a liner pool as well and he’s never had the iron stains like I do and we’re obviously on the same city water. His pool is close to 10 years old.

It’s only been a week since I replaced the water so it’s way too early to tell.
If you ever used Clorox salt then that is the likely source of your iron... Like mine.
 

carlos31820

LifeTime Supporter
Nov 22, 2010
407
Midland, Georgia
If you ever used Clorox salt then that is the likely source of your iron... Like mine.
I believe once or twice I may have used Clorox brand salt but from then on, I only used Aqua Pure salt. But I guess the damage may have been done. Honestly, I’ve never really figured out where the iron came from. It’s part of the reason I keep thinking it may come back. All my previous theories and remediation attempts have failed.

However, after this past water replacement, I removed my salt cell and did not add salt.
 

fdl9

Member
Jun 19, 2020
6
Livermore, CA
Wow, that's a pretty amazing project and story. I'm glad it worked out!
I need to do a major water exchange in my pool, but my surroundings wouldnt allow me to do this. So I'll stick to more conventional methods!
 
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