I operate a large commercial pool (guessing ~100k gallons, 20 years old) and the problems have been compiling over the last 4 years or so, I'm hoping to get everything sorted out and back to normal this year.


First off, we are starting from scratch by draining the entire pool and power washing then repainting it.

We use some type of granulated shock, and the pool is shocked every morning during pool season, and it almost seems as if we can't keep enough chlorine in the pool. We have 4 sand filters, running off of 2 pumps, and 2 chlorinators tied in. It usually seems like one chlorinator will completely empty in a day, and the other has barely eroded any tablets at all. We even put 2 or 3 tablets in each of our six skimmer baskets trying to add more chlorine into the pool.

Bather load is high end.. probably about 60 people a day, growing to around 150 a day on the weekends. Although we have it stated in the rules that no street or gym clothes are allowed in the pool, our attendants aren't strict on this. Could this be contributing to our problems in the filters and overall chemical levels?

Also, there is a constant mud-like coating on the bottom of the pool, it clouds up the water a light brownish color when you brush it. I'm going to try to tie socks on all the returns when we fill the pool back up to make sure its not coming from the filters. It could also be from the granulated shock, we try to put the shock in a bucket of pool water and mix it up, but there is always a sludgy bit of granules left in the bottom that gets in the pool. Not sure why it wont completely mix up.

As for our filters, how often should the sand be changed? In my knowledge, they are still running the same sand as they were 20 years ago. Any kind of maintenance you can do to help clean out the existing sand if I'm not supposed to change it out?

Aside from that, I'm curious as to a complete maintenance schedule for the pool, how often to backwash/how to know when backwashing is complete/etc.




Thanks in advance!