Nitrates in Pool Water: Do You Really Need to Get Rid of Them?



Worried about nitrates in your pool water? Not sure where they came from or how to get rid of them?

No stress, this article tackles all of those questions and more. Spoiler alert: It’s a lot more straightforward than you probably think.

What Are Pool Nitrates?

Well, first of all, there isn’t actually such thing as “pool nitrates” — they’re really just called nitrates.

Nitrates are a form of nitrogen. They are natural chemical compounds commonly found in soil, fertilizer, sewage, and animal waste.

It’s basically plant food, meaning the more nitrates a plant is able to absorb, the faster it will grow.

The term “pool nitrates” is in reference to nitrates found in swimming pool water, which is relevant because aquatic plants, like algae, also like to feed on nitrates.

Note: You may also come across the term “nitrites” which is also a form of nitrogen and close cousin of nitrate. Oxidizers like chlorine quickly turn nitrites into nitrates, so it’s largely irrelevant in this case.

How Do Nitrates Impact Your Pool Water?

In a properly balanced pool, nitrates have close to zero impact on the quality of your pool water.

Nitrates don’t cause your pool to consume more chlorine, they don’t make your water cloudy, and they’re also not harmful to humans — even if some poorly researched publications say otherwise.

In an unbalanced pool, however, particularly where algae have had a chance to form, nitrates are a food source that will allow algae to flourish. This can eventually lead to a green, dirty pool that is no longer safe to swim in.

So, while nitrates aren’t directly hurting your pool or the people who use it, a high volume of nitrates can accelerate an existing algae problem if it isn’t killed off quickly (through shocking).

How Do Nitrates Get Into Your Pool?

Nitrates can find their way into your swimming pool through various creative avenues, especially in rural areas.

These as the most common sources:

  • Swimmers. Sweat, oils, urine, and even feces from human beings are big drivers of nitrates in a pool. Cosmetic products like makeup and lotions also add to this.
  • Rain. Rainwater is rich in nitrates. If you haven’t covered your pool, it only takes a light shower to inject your water with a healthy dose of the little buggers.
  • Animals. Pools attract many animals like frogs, ducks, and other birds, all of which will poop in your pool. That’s without considering pets like cats and dogs dragging nitrates into the water from the lawn.
  • Water runoff. Aside from rain going directly into your pool, it also causes excess water on land to flow into pools. If you have fertilizer or manure nearby, the runoff will likely be contaminated.
  • Water source. Well water is rich in nitrates due to being exposed to all of the factors above. Septics tanks and other septic systems also produce nitrates that can find their way into your pool.

How Do You Test for Nitrates?

Since nitrates don’t directly impact the quality of your pool water, there isn’t much use in testing for them and we don’t advocate for it.

With that being said, if you’re still set on testing for nitrates, there are a couple of things you need to know.

First, the typical range for nitrates in a pool is between 10 and 30 parts per million (ppm). If your water reads way above that, consider checking the list of nitrate sources above and cutting down contamination where possible.

As for pool testing kits that look for nitrates in your water, options are limited. Not many test kits measure nitrates because most pool companies understand it serves little use to the consumer.

AquaChek 641426E Swimming Pool and Spa Nitrate/Nitrite Test Strips, 25...
AquaChek 641426E Swimming Pool and Spa Nitrate/Nitrite Test Strips, 25...

    How Do You Remove Nitrates from a Pool?

    Despite what your local pool store/pool guy may tell you, there are currently no products on the market to lower nitrates in your swimming pool.

    Nitrate is already the most oxidized form of nitrogen, so oxidizers like shock, ozone, or UV won’t have any effect. Your pool filter won’t be able to filter them out, either.

    In fact, the only way to realistically remove nitrates from pool water is to partially drain and refill, and any experienced pool owner can tell you how much fun that job is (sarcasm).

    But you don’t even need to do that.

    Yes, nitrates are food for algae, as are phosphates — but algae shouldn’t even have a chance to feast on these contaminants assuming your pool chemistry is on point. It should be long dead before then.

    Again, if you have an algae problem, it’s not because you have a high level of nitrates in your pool, it’s because you have improper balance in your water chemistry that allowed algae to take hold.

    Bottom line: Don’t waste your time removing nitrates from a swimming pool because nitrates by themselves aren’t the issue. It’s all about prevention.

    How Do You Balance Pool Water to Prevent Algae Forming?

    We could write an entire article on how to balance your pool water the right way, and we did just that.

    Don’t worry, if you just want the TLDR (too long; didn’t read), we’ve got you covered:

    1. Keep your pH level between 7.4 and 7.6.
    2. Check your total alkalinity (TA) is between 80 and 120 ppm.
    3. Maintain a chlorine level of between 1 and 3 ppm
    4. Calcium hardness level between 200 and 400 ppm.
    5. Keep your pool stabilizer level between 30 and 50 ppm.
    6. Test your water regularly (once per week, ideally)
    7. Brush and vacuum your pool regularly (once per week, ideally)
    8. Use a pool cover to prevent unnecessary contaminants
    9. Ensure proper water circulation and filtration

    Are Nitrates Worth Worrying About?

    No, they’re not.

    You’re always going to have some level of nitrates in your pool water, and trying to stay on top of them requires more time and money than it’s worth.

    As long as you keep a handle on your pool chemistry and react quickly to any algae formations, you should never need to worry about nitrates or phosphates ever again. Period.

    Categories: Pool Care, Pool Problems