When your pool water is old...

Remember when our pool started acting up?  You can refresh your memory here. In spite of the regimen of algaecide, citric acid, and flocculant, this spring we had the worst battle with stains and algae we've ever had.

It was so bad, we abandoned googling answers and went straight to asking the neighbor who owns a pool company for help. What we discovered was this: our water is old. Seriously. The same water has been in the pool for, well, every since we moved here in 2007,  and who knows how long before that.

Did you know that chlorine is a gas and to put it into pool water, chlorine tablets contain cyanuric acid as a stabilizer for the chlorine? It keeps it from breaking down under the ultraviolet rays of the sun. When the concentration of cyanuric acid grows to high levels over the years, it prevents chlorine from breaking down altogether. Since the chlorine can't release, it doesn't kill algae. So you add algaecide, which raises the copper level in the water. If your water is already prone to high levels of copper (and this happens especially if you have a pool heater), the copper in the water clings to the pool liner and creates large brownish gold stains.

Now, if this happens several years in a row, other chemicals start to break down. The cyanuric acid breaks down and somehow (magic is my theory) you get a lovely coating of purple sediment all over the flat surfaces of your pool liner.

The water can be perfectly clear, but there are brown stains and purple sand all over the place. The scientific name for this is ick. When you step out of the pool, it looks like the picture below:

Ew

So, you call your neighbor the pool company owner who explains your water is old. You drain about half the water out, refill it with fresh water, and turn over the keys to the gate to the pool guys who will tweak it until it's perfect.

And that's how you deal with old water in the pool. Next March, I will be posting about how you deal with putting in a new pool liner.