Sometimes going green is not a good thing.

Brace yourself, kiddos. It’s about to get all sciency up in here again.

We’re about to do our very own Mythbusters-esque venture in this post: Does chlorine really turn blonde hair green?

*cue exciting adventure/detective music*

While our budget is not high enough to rent a blonde to sit in several pools and hot tubs with hair immersed (nor are we that cruel to risk her colour), I have gotten to the bottom of this myth without empirical research (yes, I am that good).

Contrary to popular belief, it is not the chlorine in pools or hot tubs that turns natural or highlighted blonde hair green. What happens is that copper, either found in the water supply, metal pool fittings or plumbing, oxidizes and binds to the protein in the hair shaft, depositing its green colour. This also happens when pool water is corrosive because of low pH (acidic) or because the water is soft (low mineral content).

So, the sanitizer (chlorine) doesn’t directly turn hair green, but if the water is already corrosive, having a high level of sanitizer will increase the green effect. To combat this, the pool water balance level (not sanitizer level) should be adjusted. But fear not, you don’t have to be a scientist to maintain your pool – there is a scale called the Langlier index used to calculate how corrosive or scaling the water is, determining the proper levels of minerals needed in the water.

Confusing? Don’t worry. Here are some tips for preventing green hair from Patrizia, an Advanced Stylist at Haartek.

1. Wet your hair with fresh, clean water before swimming or hot tubbing. If the hair is already wet, it will help keep it from soaking up too much chlorinated water.

2. Apply a conditioner beforehand. This will seal the hair cuticle and prevent copper from binding to the hair.

3. Rinse your hair immediately after being in the pool or hot tub.

4. If you are regularly in the pool or hot tub, use a clarifying shampoo once a week.

5. And those of you who are daring to be retro, nothing beats an old-fashioned swimming cap to protect those golden locks. That, or not dunking your hair. Either way. Though, if you are a routine swimmer, Patrizia seriously recommends wearing a cap.

But what if you’re not careful and you come out of the pool looking like a Muppet? “Removing the green successfully depends on how porous your hair is,” says Haartek owner, Cosimo. “A clarifying shampoo can work, but sometimes your only option is to bleach it, go darker or cut it off, unfortunately.”

The moral of the story? “Take preventative measures to protect your colour,” says Patrizia. “And always check the balance level of the water.” Going green may be trendy… just not for the colour of your hair.