You asked. We answered!

Quench your curiosity with the ultimate pool Q&A

<strong>You asked. We answered!</strong>
  • Category:
  • Pool Care Education

In early May, we reached out to our social media followers to gather their toughest pool problems and most common pool care questions.

We’ve compiled the results and answered the four most common questions to help you make the most out of prime pool season. So let’s dive in!

I used to buy the HTH™ Pool Care Super Shock but can’t find it in any stores. What would be a good replacement for that?

Actually, there’s no replacement needed! HTH™ Pool Care Super Shock is still here; it just received a makeover.

With a new name – HTH™ Pool Care Shock Advanced – and a fresh, new package, it still offers the same great formula that quickly restores crystal clarity to your pool water.

Want to restock your pool shock? Find a retailer near you that offers HTH™ Pool Care Shock Advanced!

Remember, shock treating once a week helps solve 90% of most common pool water problems — like bacteria, cloudy pool water, chlorine odor and algae — within 24 hours!*

*Based on most common pool water problems

HTH™ Pool Care Shock Advanced

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I recently purchased the HTH™ Pool Care Green to Blue Advanced Shock System. There was a brownish-orangish colored product in the Pack II bags. Should that be in there?

Yes, it should! HTH™ Pool Care Green to Blue Advanced is a simple, two-pack system that works together to transform your pool water from green to blue in 24 hours.

Pack I is a strong pool shock that fights and kills green algae with Cal Hypo. Pack II contains a powerful flocculant – an agent that clumps algae particles together and drops them to the pool floor for easy vacuuming.

This flocculant may look somewhat brownish-orangish in the package. That’s perfectly normal and will be vacuumed away once HTH™ Pool Care Green to Blue Advanced has done its job!

HTH™ Pool Care Green to Blue Advanced

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What is “chlorine lock”? I heard that it’s a made-up term – is that true?

Chlorine lock is real – and it’s an important issue for pool owners to be aware of. Simply put, chlorine lock refers to a condition that occurs in swimming pools when the chlorine levels become ineffective in sanitizing the water.

Chlorine lock can be caused by various factors including high pH levels or the presence of contaminants like algae and organic matter. It can also be caused by excessive cyanuric acid (CYA), a chemical compound commonly found in traditional, stabilized chlorine sanitizer and shock products.

CYA does not burn off in the sun like chlorine does. So, when you add stabilized chlorine products to your pool water, the CYA builds up and causes overstabilization — commonly known as chlorine lock.

Chlorine lock lowers the effectiveness of chlorine, which can result in issues such as:

  • Cloudy pool water
  • Unpleasant odors
  • Red eyes and/or itchy skin
  • Unsafe/unhealthy swimming conditions

The solution for chlorine lock? Drain the swimming pool (at least partially), rebalance the water and refill the pool. Or prevent it from happening in the first place with HTH™ sanitizers and shocks which do not contain any CYA.


I read that mustard algae is resistant to chlorine. So should I use shock or an algaecide to treat it?

This is a great question! As one of the three most common types of pool water algae you need to watch out for, mustard algae is the type that contains chlorine-resistant compounds. Yet it can be eliminated!

Treatment may require both shock and algaecide. But first, you’ll want to test and balance your pool water and be sure your filter is clean. For step-by-step instructions on combatting and preventing algae, check out our Algae Basics for Beginners blog post

We loved getting these questions!

Is there more you want to know? Are there topics you want us to cover in the weeks ahead? Let us know via chat or share your thoughts on your favorite social platform. Because we’re here to help!

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