Should you ever completely drain your pool?

[grimmpatrick]

Living in Mesa, AZ, it's common knowledge that your pool should be completely drained and the water replaced every 1-5 years, depending on who you ask. We have very hard water and the thought is that combined with the chemicals that are added require a complete drain and refill periodically.

On another forum, answers varied from never to annually. I would like to hear from this community, as this is the place that empowered me to fire the pool man, clear up my pool, and helped me to see the bottom again.

 

[pooldv]

There are really only two reasons to drain a pool, high CH and high CYA. Neither will usually get better with time. But, high CH can be managed up to levels in the 800-1000 range. Lots of people here do it. Watch your CSI level in Poolmath and keep it in range by adjusting PH and TA to compensate for the high CH to prevent scaling. Once you do get up to 800-1000 ppm a partial drain and refill is needed. But I would only replace 1/2 to 2/3 of the water.

More on scale and CSI here,
Pool School - Calcium Scaling
Langelier and Calcite Saturation Indices (LSI and CSI)

 

[JoyfulNoise]

One thing to realize is this - the water in your pool today is NOT the same the water that was in your pool at startup. Your pool is continually evaporating water and being refilled with fresh water. So what really determines when you might need to partially drain your pool (full, total draining is very rare) is how diligent you are in caring for your pool water and maintain proper chemical balance. If you're not diligent and choose to use solid chlorine products, then, as pooldv said, your CYA and/or CH will build up to intolerable levels and you'll have to drain. If you are careful with your pool water and do things like using a pool cover and refilling with winter rain waters, then you can probably go 10 years or more without ever having to drain any significant amount of water off your pool.

The answer is - it depends on the pool owner.....

 

[mas985]

It also depends on the fill water. High CH fill water combined with high evaporation rates can rapidly increase CH levels within a couple of years.

 

[eqbob]

Don't forget that completely draining a pool can be "dangerous" depending on the water table and hydrostatic lift.

 

[rick458]

We had several pool shells float up from the last big rain we had here, so if you are going to completely drain it make sure the water table is below the bottom of your pool.