Back when I was an aquatics director at a special recreation district in Colorado, I operated two indoor and three outdoor pools. One of those outdoor pools was built in 1956 and was the reason for the formation of the special recreation district.
This was a very substantial pool, built in the style of the old WPA structures with thick walls and iron pipes. It had an old 110V workhorse of a pump that still ran after several floods of the underground equipment room. The pool filter was a gravity anthracite coal filter with three large chambers. Water entered the top of the filter, settled through the coal bed and was pumped back into the pool. It was a great pool that we kept together literally with baling wire and bubble gum.
We had just filled the pool for the season, and had balanced and chlorinated the water. Our large chlorine shipment had been delivered and everything was in shipshape. The pool was set to open in another week, so we had plenty of time to get the water heated and the facility prepped for another season of memory making.
But overnight, everything changed.
Shortly after we left for the day, one of the ubiquitous Colorado thunderstorms rolled into town and knocked out power at the pool. With the electricity out, the pump stopped and water settled throughout the system.
Unfortunately, a minor, seemingly inconsequential check valve on an aging chemical pump failed to get the message to close, and it stayed open. So overnight, it drained 500 gallons of 12 percent bleach into that anthracite filter. Now chlorine fully mixed with pool water runs through that filter all the time, however, not at that strength.
Slowly, as the chlorine tank drained, the filter media dissolved.
Oblivious to the overnight malfunction, I arrived in the morning with high hopes of completing a few small repairs and moving on to getting my other two outdoor pools up for the season. I flipped the switch on the pool pump and it hummed to life, pumping 600 gallons per minute through the filter and into the pool.
After about 15 minutes, I climbed out of the underground pump room to see my pristine blue pool now a lovely deep brown ale color. It even had a head of foam closest to the pool inlets. This was a disaster! I quickly shut down the pump, but the damage was done. I investigated what had happened, fixed the check valve, drained the pool and refilled it. The color stayed that beautiful shade of ale! That was fine for a microbrewery, but certainly would bring out the red pen of our local health code enforcers.
After further investigation, I found the filter to be a hopeless loss. I also learned that I could not get regulatory approval to replace the granular coal filter media. So I was forced to adapt the filter to become a gravity sand and gravel filter.
It took three weeks to dig out what was left of the old media, adapt the water collectors, add the new sand and gravel, and refill and balance the pool. Many of our regular pool rats gave me the evil eye while we replaced the filter.
In the end, a $15 part cost me $15,000 in lost revenue. And I lost the first two weeks of the summer season, not to mention a good chunk of my budget.