Removing your cover only to reveal a hot tub full of green water can be quite a shock. While dumping in a ton of chemicals is a common initial reaction, it’s best to take a moment to regain your thoughts before acting.
Green water is the result of an algae bloom. While there are a few potential culprits, a lack of chlorine is the most prevalent offender in hot tub water cases. Without chlorine to disinfect the water, algae is able to proliferate. Once there is enough of it in your hot tub, the blooming process is just about inevitable. Once green, your water is unsafe to bathe in and will become a spawning ground for insects if left uncared for.
A 2nd reason how green water can grow in a hot tub is because of large amounts of pollen. If your hot tub is in an area with a significant amount of natural surrounds or is left for long periods of time without a cover, pollen will build-up in the water. Because it’s able to bypass the filters, it builds-up in the water. Once enough of it has nestled its way into the tub’s pumping system, your water turns green.
Green water caused by a lack of chlorine should be treated with a shocking treatment of chlorine and algaecide. This treatment in your hot tub will make your water go initially cloudy, then clear up once the algae is killed.
For cases when the green water is caused by pollen, it’s a little more difficult to deal with. Adding a filter sock over your filter will help catch some pollen, while using a clarifying agent such as Clean ‘N Clear will do the rest. Once done, if your water hasn’t returned to its natural colour, you’ll have to drain the tub. Once drained, be sure to thoroughly wipe down the entire surface of the hot tub.
Remember to always test your hot tub water every few weeks to prevent such occurrences as this.