The Day the Pool Exploded

In Blog by TMI Sustainable Aquatics

This week’s installment is brought to you by our associate and East coast rep, Paul Blake. Paul is a veteran of the pool industry with many stories to tell. This is just one of them.

Geysers - really cool at Yellowstone, not so cool in your pool.

Geysers – really cool at Yellowstone, not so cool in your pool.

I was in my second year operating this complex, a very large and beautiful municipal facility with three pools on Long Island. Built in the late 1950’s, all three pools were running on gas chlorine, caustic soda, and huge old rapid sand filters.

Back in the 50’s, it was common to run multiple pools on one single filtration system, and that was the case with this facility, as both the 550,000 gallon main pool, and the 12,000 gallon wading pool were filtered by the same two tanks.

I was told when I became the operator of the pools, that at some point in the mid 1960’s, the circulation system for the wading pool began to malfunction, and it became difficult to maintain the water level in the pool, as well as the flow rate. At some point, one of the maintenance employees did a little re-plumbing of the wading pool, with the result that the pool filled itself through the main drain, and the water circulated back to the pump house through the return inlets on the side of the pool.

Fast forward to 1987, and my two pump house operators are both nice, polite, lazy college kids. For the first four or five weeks, I really sat on them and made sure they were doing things ‘by the book’. As the season went on, the main office got busier and busier, and I had less time to babysit the pump rooms. And therein lay the problem.

In CPO® Courses, we stress the importance of reading gauges on a daily basis, and paying attention to them when they change. Anyone who operated those old rapid sand tanks knows that they used to blow off LOTS of air during their operation, especially with 30 year old valves and other parts. And there were air vents on top of the tanks, which automatically bled the air out – in theory, at least. Over time however, the inner workings of these bleed valves must have gotten dirty, or clogged, or bent; I’m still not sure. All I know is something was wrong.

So what happened next, I suppose, was inevitable. The kid running the pump room came into the Office and said, ‘something weird is going on, the wading pool has water coming back into it through the return lines.’ We got up and went outside, and sure enough, we had a nice flow of water returning to the wading pool through the inlets. Watched it for a few minutes, all seemed okay, we returned to the office and (stupidly) assumed something had just ‘corrected’ itself in the pump room. Until about 10 minutes later, that is.

Suddenly we heard a very loud ‘THUMP-WOOSH’ followed by what sounded like a waterfall, then the sound of multiple lifeguard whistles, all blowing the dreaded ‘long’ whistle, which was our call for an emergency. We rushed out onto the pool deck and saw patrons running and scrambling out of the main pool, screeching and yelling, while from the diving board end of the pool, a dark brown underwater cloud was billowing towards the shallow end of the pool. Within just a few minutes, the entire pool was brown and turbid, really nasty looking.

At that point, we realized what had happened. The air bleed valves on the filter tanks had jammed, and were not releasing any air, which caused a build up in the tanks. Without properly monitoring the gauges on the tanks, the pressure built up to the point where it ‘blew back’ through the influent side of the tank, which caused a 10 – 12 foot water spout to shoot up from our main drains, and blew all of the accumulated dirt, oil, and debris in the filter tank back into the pool.

We ended up keeping that pool closed all day and night, and only re-opened it the next day around noon time. Patrons were nervous about going in, even though by then we’d cleared the water up and the chemistry was fine, so we had our lifeguards get in and swim laps back and forth, and eventually the people realized that things were okay.

Of course, we did have a fun filled 24 hours answering questions about what happened. And as with most places, the rumors that got started were pretty wild, and the speed with which they spread throughout the town was startling. It wasn’t 10 minutes after the event happened that we started to get phone calls asking if it was true that the pool had ‘exploded’. The nastiest rumor we had to squelch was that raw sewerage had somehow gotten into the system and was what turned the water dark brown.

Just another fun filled day at the pool, and a great lesson for operators everywhere that even though the gauges on our systems are some of the smallest components, they certainly require careful monitoring and attention, especially when they change.

~Paul Blake