Tarp method in-place water replacement

Newdude

Well-known member
Jun 16, 2019
3,756
NY
You may have accidentally invented a new way to buy some time when people have large liner rips.
Awesome job and pretty cool screwup.

After the initial panic, (I hear ya, I would have needed fresh pants myself) I would have kissed it goodbye and cut the tarp with a Sheetrock knife at the drains, the pump, the hose, the stairs and anywhere else I could get a fold or flap without worrying about cutting the liner. It would have taken a while but it would have drained like cutting the actual liner just the same.

Whatever parts of the tarp you saved will come in handy for something else I’m sure.
 

carlos31820

LifeTime Supporter
Nov 22, 2010
407
Midland, Georgia
I feared that might happen. Glad you were able to recover.

You can throw out that pair of underwear you were wearing, I’m sure it’s not worth cleaning them 💩💩💩
I immediately thought about your prophetic post about not draining all the way.

For real, I was panic-stricken when I pulled on that tarp and it did not budge a millimeter. It was like it was super-glued to the liner.

I was picturing myself in scuba gear carefully cutting the tarp without somehow cutting the liner. It was a frightful 10 minutes or so for sure.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,062
Tucson, AZ
I’m always very wary to recommend the tarp method as there are just so many things that can go wrong as well as it being dangerous to have a tarp of that size floating on the pool. I imagine someone falling in and drowning because they got caught up in a submerged tarp. Then there’s just the shear weight of water sitting against a tarp. I liked your solution of pushing water between the tarp and the liner using a hose but I think the tear at the bottom by the submersible pump helped that.

Either way, good job. Now let’s hope your chemistry balances out quickly and your metal stains stay away.
 
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JamesW

TFP Expert
Mar 2, 2011
19,794
Then there’s just the shear weight of water sitting against a tarp.
There should never be any weight being supported by the tarp. The tarp should never be under any stress or tension.

The edges of the tarp should never be secured in a way that would allow tension to develop in the tarp.

A few waterbags around the edges should keep the tarp from blowing around in the wind, but they would pull in if the tarp began to develop any tension.
 

JamesW

TFP Expert
Mar 2, 2011
19,794
You can't fully drain a vinyl pool because the liner would come loose.

For any pool, sometimes the ground water will create a floating risk.

In very hot conditions, a plaster pool can be damaged when the plaster overheats.
 
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duraleigh

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In The Industry
Apr 1, 2007
34,056
Sebring, Florida
I think the work in this thread is nothing short of spectacular.
You should get a very good dilution from what you have accomplished with the tarp.
And that's the bottom line. I think it will also be very effective.

The Tarp Method was first mentioned on this forum and possibly Poolforum some 13-15 years ago. The theory was wonderful but I can remember only one other trying it and it wasn't documented particularly well but was reported successful. That method pretty much morphed into the simultaneous drain and refill which we now suggest........not as effective but a WHOLE lot easier

Did you happen to have a meter on your incoming water? That would tell you pretty close to how much "new" water you have.

Excellent work....Thanks for sharing.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,062
Tucson, AZ
I’d rather do an exchange-drain than the tarp method. While I appreciate Carlos’ efforts and attention to detail, there are just too many things that can go wrong and, in all honesty, many people can not be trusted to think it through which can lead to overzealous execution and accidents. As you can see from this thread, Carlos spent a lot of time thinking this through and getting everything setup and in place .... and still had a problem. The tarp had literally turned into another liner in his pool and was pegged to the pool surface by the weight of a hundred thousand plus pounds of water. If that sub pump hadn’t torn a hole in the tarp, getting that tarp out of the pool would have been a nightmare and running a knife anywhere near the liner to cut the tarp would have risked the entire pool surface.

Love the thread and the outcome was positive but it only confirms my position that the tarp-method is not “ready for the masses”.

TFP is, after all, all about keeping it simple, right 😉😛
 

JamesW

TFP Expert
Mar 2, 2011
19,794
It really wouldn't be that hard to get the tarp loose.

In any case, like anything else, people have to decide what they feel comfortable doing.

I don't know that I would recommend it or against it.

The main thing is to think it through and keep an eye on things.
 
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YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
13,856
Evans, Georgia
I recall a guy doing a tarp exchange at night.... blue tarp....comes to mind. *I* thought it was brilliant.

Obviously easier to do on smaller pools than Carlos'. We never have figured out the source of your metals, have we Carlos?? I recall your posts and attemps at management well.

Maddie :flower:
 
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carlos31820

LifeTime Supporter
Nov 22, 2010
407
Midland, Georgia
I recall a guy doing a tarp exchange at night.... blue tarp....comes to mind. *I* thought it was brilliant.

Obviously easier to do on smaller pools than Carlos'. We never have figured out the source of your metals, have we Carlos?? I recall your posts and attemps at management well.

Maddie :flower:
Hi Maddie, the source of my metals has proven to be quite the mystery. My neighbor with same source water as me has no such issues with his 10 year old pool. My other neighbor, however, did have the problem until his liner was replaced and all his water got replaced as expected.

Between his results and my out-of-whack water chemistry (super high phosphates), recent high chlorine demand, etc I decided I just needed to hit the reset button and really replace most of my water.

I was going through a case of Metal Magic every 6 weeks at over $200. It was just unsustainable.
 

carlos31820

LifeTime Supporter
Nov 22, 2010
407
Midland, Georgia
I think the work in this thread is nothing short of spectacular. And that's the bottom line. I think it will also be very effective.

The Tarp Method was first mentioned on this forum and possibly Poolforum some 13-15 years ago. The theory was wonderful but I can remember only one other trying it and it wasn't documented particularly well but was reported successful. That method pretty much morphed into the simultaneous drain and refill which we now suggest........not as effective but a WHOLE lot easier

Did you happen to have a meter on your incoming water? That would tell you pretty close to how much "new" water you have.

Excellent work....Thanks for sharing.
It appears that my water replacement replaced most of the water. My CYA dropped from 60 to zero. My pH, hardness, and alkalinity match what my tap water tested at.

pH: 7.8
CH: 20
Alk: 20

I'm also already able to hold chlorine @ 2.5 ppm (keeping it a little low for now) and I had done a huge ascorbic acid treatment 24 hours before draining it. I was expecting to have high chlorine demand with the leftover water since I used 4.5 lbs of ascorbic acid for my 24k gallon pool.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,062
Tucson, AZ
With water that low in both CH and alkalinity, use cal-hypo to chlorinate (it’ll save your back on lugging bleach bottles around). You can easily afford the calcium and it will slightly elevate your TA with use.
 

JimMarshall

Gold Supporter
TFP Guide
Jun 5, 2017
983
Oil City PA
Tarp water replacement is still progressing as expected. I've added some tarp clips and paracord that will stretch and allow the tarp to slide just past the coping but keep it from falling in the water.

The tarp is already resting on the bottom of the shallow end and is about 65 inches from the deck in the deep end. I estimate it will go about another 2 feet or so before I run out of tarp. I'll cut the water off before going to bed so I can keep an eye on it tomorrow as it continues.

View attachment 151625

View attachment 151626

View attachment 151627
This picture makes me wish I had a grey liner. That’s a pretty water color!
 
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carlos31820

LifeTime Supporter
Nov 22, 2010
407
Midland, Georgia
Did water test this morning. Chlorine is where I left it last night (3.5 ppm), CYA still close to zero so I added more CYA to bring it up to around 20 for now, retest and add more to land between 30 and 40.

I forgot to mention that for the first time in years, I was able to do the CH test without the sample turning purple or turning back to red (fading endpoint) due to metal interference. So for now it’s fairly obvious my new water replaced most of the old water and the current water chemistry is in a much better place.
 

JimMarshall

Gold Supporter
TFP Guide
Jun 5, 2017
983
Oil City PA
Did water test this morning. Chlorine is where I left it last night (3.5 ppm), CYA still close to zero so I added more CYA to bring it up to around 20 for now, retest and add more to land between 30 and 40.

I forgot to mention that for the first time in years, I was able to do the CH test without the sample turning purple or turning back to red (fading endpoint) due to metal interference. So for now it’s fairly obvious my new water replaced most of the old water and the current water chemistry is in a much better place.
Great to hear that you had a (mostly) successful water change. Sounds like you accomplished your goal
 
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Yev

Well-known member
Jul 29, 2014
471
Independence, KY
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.
 
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