Removing stains and draining - is this a good idea?

lborne

Well-known member
Jun 29, 2009
467
Vero Beach, FL
Due to some issues just after building the pool, we got a lot of iron dust in the pool due to rebar grinding, etc. and had severe staining on the floors and walls. I was able to get it out with citric acid and continued to use a sequestering agent to keep it out. However, I stopped using the sequestering agent and now the stains have appeared on the walls - not nearly as bad as before, but noticeable.

My plan is to remove the stains again with citric acid and then drain the water so that I don't have to keep adding sequesterant.

I will remove half at first - refill, remove half and then refill which should leave only 25% old metal water. Water is cheaper than renting a pump to drain the water under to pool to keep it from floating.

Any other way I should do this? Any other things I need to consider?
 

Melt In The Sun

TFP Expert
LifeTime Supporter
Oct 29, 2009
3,899
Tucson, AZ
Sounds like a reasonable plan, but remember to budget for a new fill's worth of CYA, calcium, salt, etc. When you consider that, it may be cheaper to buy sequesterant for a while.
 

lborne

Well-known member
Jun 29, 2009
467
Vero Beach, FL
Melt In The Sun said:
Sounds like a reasonable plan, but remember to budget for a new fill's worth of CYA, calcium, salt, etc. When you consider that, it may be cheaper to buy sequesterant for a while.

Yes, but not trouble free. I really love my SWG and I added a home made muratic acid injector per instructions on a post and I've got it so that I hardly do anything to the pool.

I add salt maybe 1x a year. Refill my 30 gallon acid dispenser every 4 -6 months. I have an auto pool vac and having the screen over the pool makes it so I only need to clean the cartridge filter a few times a year.

But thanks for the input. I did figure all those costs. My CH is high too, so is yet another reason to refill.
 

UnderWaterVanya

TFP Expert
LifeTime Supporter
Jun 14, 2012
2,589
Mint Hill, NC
You can try the method we hear about but never see done - a large plastic sheet over the water that segments the water into new and old and then drain from under the sheet and fill from over it.
 

lborne

Well-known member
Jun 29, 2009
467
Vero Beach, FL
UnderWaterVanya said:
You can try the method we hear about but never see done - a large plastic sheet over the water that segments the water into new and old and then drain from under the sheet and fill from over it.

Great idea. Off to Sams Club for the large box of saran wrap. Seriously - where can I get a sheet that large? I have tarps, but none are as big as the pool.
 

SebringDon

Well-known member
Oct 1, 2012
91
Sebring, Florida
Buy an oversize solar cover. After you're done, cut it down into a couple of covers, use one and store one for a couple years until the first one dies. I bought a 21 * 42 ft solar cover for my 12 x 36 pool from VMInnovations cheaper than I could buy a properly-sized one from anywhere else. If I had been thinking I would have bought a 24 * 42 and had two, one to store. A 24 * 50 would have been more than big enough to do the drain and fill routine with.
 

UnderWaterVanya

TFP Expert
LifeTime Supporter
Jun 14, 2012
2,589
Mint Hill, NC
The solar covers float...how would that work?

I think you hit one of the reasons this is not done often... Where do you find a sheet like this? Maybe the paint store? They often have plastic drop cloths.

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Swampwoman

TFP Expert
LifeTime Supporter
Apr 27, 2012
3,835
Grand Rapids, MI
Home despot has boxes of 6 mil visqeen but you'd have to tape it together with duct tape to get the width. It's used in encapsulation of crawlspaces. Comes in boxes up to 100 feet. Cheaper than a solar cover.
With solar cover, idea is to buy it several feet larger than pool opening, then cut it down when you're done to reuse it.
 

SebringDon

Well-known member
Oct 1, 2012
91
Sebring, Florida
UnderWaterVanya said:
The solar covers float...how would that work?

I think you hit one of the reasons this is not done often... Where do you find a sheet like this? Maybe the paint store? They often have plastic drop cloths.

Sent via Tapatalk...
Well, it was just an idea. :) A solar cover just the size of the pool wouldn't work, as it would float to the top as new water ran off and mixed with the old. However, If you had a solar cover large enough to cover the pool and go down the sides, you'd be isolating the water below from the water on top. There'd be no way for the solar cover to float up over the water that was trapped on top of it. I'd use it bubble-side up so that the bubbles didn't get scraped along the edge and side as it settled toward the bottom of the pool.

My pool's deepest spot is 5' 5", so a cover 24' wide and 48' long would still have its edges above the new waterline and be acting as a container for all the new water even when all the old water was gone. All you'd have to do is push an edge under the new water and it would flow down into the void below, allowing the cover to be floated to the top and removed.

Or am I missing something?
 

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lborne

Well-known member
Jun 29, 2009
467
Vero Beach, FL
UPDATE and a few more questions

Hi,

I have bought asorbic acid instead of citric and am ready to begin my stain removal, but have a couple issues.

1. The pool is now at 70 degrees F. Will the lower temp inhibit the strain removal? What is the minimum temp that I should do the stain removal?

2. My FC is still too high. It was 9 and now, several weeks later, is only down to 6. I want to get this done, but know that I should drop FC down to 1 so that it does not use up the acid. Is there something I can do to quickly lower the FC?
 

lborne

Well-known member
Jun 29, 2009
467
Vero Beach, FL
Yes, I might try the tarp idea. But first I need to get the metal off the plaster and into the water. I can't do this until my chlorine is low but it is not going down with these cold temps.
 

UnderWaterVanya

TFP Expert
LifeTime Supporter
Jun 14, 2012
2,589
Mint Hill, NC
lborne said:
Yes, I might try the tarp idea. But first I need to get the metal off the plaster and into the water. I can't do this until my chlorine is low but it is not going down with these cold temps.
There are chemical options to lower chlorine.

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lborne

Well-known member
Jun 29, 2009
467
Vero Beach, FL
UnderWaterVanya said:
There are chemical options to lower chlorine.

Sent via Tapatalk...

Yes, and that is probably what I will do because I also need to schedule this when I have a full day. Hopefully very soon. I will post my results here about the staining and the water change.
 

lborne

Well-known member
Jun 29, 2009
467
Vero Beach, FL
UPDATE

Today I finally had time to try to remove the stains. I had the chlorine at zero and added the AA. An hour later - no change. I added citirc acid. Still, the stains were still there, although lessened a bit. So after 6 hours, and still the stains persisted, I dumped in 4 gallons of muratic acid. 1 hour later, the stains were gone. I'm leaving it over night to get rid of a few spots that still are stubborn. Will update in a day or two.
 

lborne

Well-known member
Jun 29, 2009
467
Vero Beach, FL
Update 2

I did not circulate the water with the high acid concentration, so I just let it sit and brushed. I then pumped out about 75% of the water. I was only going to do 50%, but I could tell that the water table was low as we have a ditch in the back and it was dry and below the level of the bottom of the pool. I then filled the pool, drained it down 75% again, and will refill tonight. Maybe I took a little life out of the plaster, but it sure is nice seeing it bright and refreshed with no stains.

The main reason I replaced the water is because I don't want to have to keep adding sequestering agents.
 
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