Why & When Do I Need To Drain My Swimming Pool

by Knut Borgen

Is it true that there is a definite life expectancy time for water in a pool, even if rain and topping up due to evaporation takes place on a continuous basis.

Some people have told me max 5 years.

Thanks for your question Knut

The life expectancy of pool water depends on a variety of factors:

Use of pool
Type of water (well, tap, pool water delivery)
Hardness of the water
Total Dissolved Solids (TDS)
How well you take care of the chemicals; i.e. excessive use of chlorine, muriatic acid, algaecides, etc...

So the real issue is when to drain and re-fill the pool. The measurement of TDS in pool water can be influenced by many factors; the chemicals we add to adjust the pH, chlorine, water hardness, alkalinity, dust, dirt, human waste, will increase the level.

The maximum acceptable level for TDS is 1,500ppm. If you allow the pool to get above this you run the risk of staining, the water might become cloudy, and it will reduce the effectiveness of the other chemicals.

You can have your pool water tested for TDS at a local pool store. If it's close to 1,500ppm, then it might be time for a drain and re-fill.

So TDS is the answer to your question. Drain and re-fill when the TDS reaches, or is close, to that level. You want to drain because the pool requires it, not because it's the last Saturday of September 2010.


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Aug 07, 2013
Drained tds #'s Very High, Now H2O Not Clear ?
by: Anonymous

O.K. we just had our pool drained and refilled. But here's the problem... or question....

Why does our pool look cloudy? It's never looked this bad. The water was clear before this was done?

Thanks for the question

What I gather from the question is the pool was completely drained and refilled. Did you use city or well water? Was it cloudy right after it was filled or was the filter on for a period of time? Have you added any chemicals yet?

I'd like to have your complete chemical readings, the actual numbers:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper) and names of any algaecides you may have used along with clarifiers, phosphate removers, and/or flocs. It makes troubleshooting much easier and the process of clearing up your pool will go much faster.

If you simply drained and filled the pool, allowed it to sit for a couple of minutes to settle then it turned cloudy immediately afterwards without adding any chemicals and no filtration, and used city water, I'd encourage you to talk to your local city water company. If there are other variables, I need to know about them to help with your issue.


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