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draining an inground pool ?

Posted by mastiff_lover (My Page) on
Thu, Jul 14, 11 at 20:05

After taking my water sample to my local pool supply company, I was told my total dissolved solids is at 4500 ppm. I was advised that my pool needs to be drained at least half way to lower the solids reading to under 2500. Is it ok to completely empty a Pebble Tech pool overnight and refill the next day without having issues of ruining the (gunite) pool shell? Also what other precautions must I take to ensure not to damage the pool in any way. The pool is about 13000 gallons and is 36' X 20' freeform but only has a max. debt of 6' in deep end and 3' in shallow and also has a beach entry that reduces the total gallons considerably. thanks in advance for your help..


Follow-Up Postings:

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RE: draining an inground pool ?

First: I don't suggest ever dumping more than 1/3 of a pool's volume at a time. God forbid that there is water under the pool. If the water outside of a shell is more than an inch or two above the level inside the pool, the shell can start to exert upwards pressures, aka buoyancy. Too much and up it comes, either entirely or in parts. Gunite pools are not designed for this type of stress.

Second: If you have a salt cell, subtract the salt's ppm. Then subtract the Calcium Hardness and Stabilizer. The only way these can be different from one day to the next is through dilution or reverse osmosis.

TDS is another of those "The Pool Store Is Educated and you aren't" words meant to instill fear in you for your pool's health if you don't trust the store's personnel's wisdom and Computer Printout. Ah, the power of the written word. TDS is a generic term that has very little meaning when it comes to pool chemistry. It basically what it says but doesn't account for the things you may need in the water or those that are, by and large, harmless, like salt under 4200 ppm. You're being pool stored by either self serving or ignorant people. Computerized printouts are often skewed toward selling you more chems.

With those dimensions, I have a hard time seeing it at only 13000 gallons. 20 to 24K, sure, but 13K seems really light.

I would like to know what the levels were for Salt (even if you don't have a cell) FC or TC, CC, Alk, pH, CH, and CYA. I would also like to know what equipment you have and any water features. The use of testing strips for everything above except salt should be avoided.

Color changing drop tests such as those used in "professional" test kits is encouraged as they tend to be more definitive and accurate. They aren't hard to use either. They will save you money in chem usage and service calls for chemistry related problems. It can set you back on the initial cost (usually about $100) but that is a one hour service call.

Understanding your pool's chem needs seems to be an area you need some assistance with. To get the truth, go to troublefreepools.com and read the pool school. Its free and an eye opening experience. I point all my customers there. Every single one of them. And not because I have any vested financial interest there either. I don't but am considered a Special Contributor there for assisting on their forum, just as I do here and other forums.

Scott


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RE: draining an inground pool ?

Scott be easy on Pool Stores I happen to own one.... and TDS is not even tested or talked about in my store.


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RE: draining an inground pool ?

Sorry muddy_water

and to any other forum contributors.

Still, I see too many times people being given low quality advice to unsuspecting pool owners. It costs them dearly. And it costs everyone else when pool owners get it in their head that everyone in the industry is that way, This is one of the biggest reasons I and the other regular contributors that are in the industry participate on this and other forums, to counter the self serving Neanderthals that don't care about anyone else but themselves.

Scott


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RE: draining an inground pool ?

Ahhhhhhhhhhhhhhh I was just Kidding....But there are pool stores that really do care out there and Web sites also that do. At my store if I can't clear up a pool. I go to the customers house free of charge to get it cleared up.


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RE: draining an inground pool ?

thanks Scott.. I will catch up with troublefreepools.com. By the way my #'s are as follows...

Chlorine 2.0
PH 7.6
Alkalinity 100
conditioner 100
Salt 3100. was forrmly a salt pool but chlorine generator recently stopped working after 5 years so now I'm using pucks
TDS 4000
Phosphate 0

the store employee was trying to tell me that having such a high reading of TDS makes the maintenance that much harder to keep everything stable and balanced.
I originally went to the store to have my conditioner checked as I felt my Chlorine was burning off to quickly.. but the weather has been 90 - 95 degrees over the last week or two.. thanks again


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RE: draining an inground pool ?

The big problem is the the stabilizer (CYA) level. It's way too high and using tabs will make it go higher.

You want your Free Chlorine (FC) to be about 10% of the CYA level. In your case, that would mean at least 10 ppm. This isn't reasonable for a tablet fed pool. Trying to maintain a shocking level isn't easy either. That would be 50 to 100 ppm FC. Good luck there.

The solution is dilution. 25 to 33% at a clip, three or four times. That means dumping to waste 1/4 to 1/3 of the pool and refilling. CYA, like salt and calcium, do not break down. The stay in the water. Diluting the water is the primary way these items are removed.

There are some areas in San Diego where a truck based reverse osmosis service exists than can do it and this saves the water.

FWIT, without diluting the pool water sample, 100ppm is as high as can be accurately measured as far as I know. Your CYA level may actually be higher and thus, may require further dilution.

The reason I recommend only 1/4 to 1/3 of a pool's volume at a time is the risks of high water table induced problems such as pop ups and liner floats.If you have a dry well under the pool, hook it up to pull out the water under the pool first.

Scott


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