Phosphates Don’t Cause Algae… They Fund It.
I don’t get excited very often about pool chemicals.
In fact, if you’ve followed me for very long, you know I’m usually the guy telling people not to buy another bottle of something.
So when I tell you I think I’ve found something that genuinely changes the way I look at phosphate removal…
…pay attention.
For years, I’ve had one major complaint about phosphate removers.
It was never that they didn’t work.
They absolutely worked.
My problem was how they worked.
Traditional liquid phosphate removers often solved one problem…
…by creating another.
The water became cloudy.
The filter loaded up.
Filter pressure increased.
Flow and turnover decreased.
Circulation suffered.
As a service company maintaining well over 600 residential swimming pools, that wasn’t a trade I was happy making.
I’ve always believed pool care should be about solving problems…
not trading one problem for another.
That’s why I recommend borates.
That’s why I like Culator Metal Eliminator.
And that’s exactly why I’m so excited about PhosLocker.
Not because it’s the first product that removes phosphates.
Traditional phosphate removers already do that.
I’m excited because it’s the first phosphate-removal product I’ve personally used that fits my maintenance philosophy.
It removes phosphates…
without intentionally creating another maintenance problem.
For me…
That’s a game changer.
Before I explain why, let’s talk about phosphates.
My Philosophy Has Never Changed
Our company’s goal has never changed.
Kill algae faster than it can multiply.
Everything else supports that mission.
If algae dies faster than it reproduces…
It never becomes a problem.
For years that has meant maintaining the proper free chlorine level for the pool’s cyanuric acid level (FC ratio), maintaining approximately 50 ppm borates, keeping the pH in a reasonable range, and staying ahead of what I call my Five Pillars of Pool Care.
- Water Chemistry
- Circulation
- Filtration
- Removing Organics
- Brushing
When those five pillars stay strong…
Algae rarely gets an opportunity to establish itself.
That’s why my opinion on phosphates has always been a little different from much of the industry.
Phosphates don’t cause algae…they fund it.
Think of phosphates as algae’s grocery store.
Or its fuel station.
Or an all-you-can-eat buffet.
They’re a resource.
But algae still has to survive long enough to enjoy the buffet.
If I’m killing algae faster than it can multiply…
I don’t spend much time worrying about how much food it has.
But…
If I can safely remove algae’s food source without creating new maintenance problems, then why wouldn’t I?
That’s where my thinking has evolved.
I’m no longer asking whether phosphate removal has value.
It absolutely does.
The question has become…
Can I remove phosphates without creating another problem?
Until now…
I didn’t think the answer was yes.
When Phosphates Suddenly Matter
Life happens.
Maybe you get four straight days of heavy rain.
Maybe the kids invite half the neighborhood over for a weekend pool party.
Maybe a dead opossum decides your skimmer is the perfect place to spend its final days.
Or maybe Uncle Eddie spends all afternoon floating around after a few too many beers, bringing with him some questionable hygiene and a lot more organic contamination than anyone wanted.
Whatever the reason…
Your chlorine falls behind.
Now you’re operating in a chlorine deficit.
That’s when phosphates suddenly become important.
The algae that survives isn’t just surviving anymore.
It’s standing in front of an all-you-can-eat buffet.
Now it has everything it needs to reproduce rapidly.
That’s why I don’t say phosphates cause algae.
They don’t.
They fund it.
They make mistakes more expensive.
They make recovery harder.
The faster algae can reproduce…
The harder chlorine has to work to catch back up.
Some Pools Simply Need More Help
Not every pool is equally easy to maintain.
Some pools have heavy tree cover.
Some receive fertilizer runoff.
Some have enormous swimmer loads.
Some owners travel frequently.
Some pools have poor circulation because of their design.
Some have undersized plumbing.
Some have undersized or aging filters.
Some have salt chlorine generators that simply can’t produce chlorine fast enough during the hottest months of the year.
Some have equipment that’s worn and no longer performing at its best.
Some have dead spots where water movement is poor.
Some pools simply have a much heavier workload than others.
Those pools don’t have the same margin for error.
Even when the owner is doing a good job, the pool’s design, equipment condition, environmental load, or overall demand may simply make it difficult to consistently kill algae faster than it can multiply.
Those are exactly the pools where phosphate removal becomes much more valuable.
Removing algae’s food source doesn’t replace chlorine.
It doesn’t replace good circulation.
It doesn’t replace brushing.
It doesn’t replace filtration.
But it does remove one more advantage algae has.
And sometimes that’s exactly the edge you need.
You Can’t Keep Phosphates Out
One of the biggest mistakes I see is people trying to maintain zero phosphates.
That’s almost impossible.
Phosphates are everywhere.
They enter our pools through:
- Fill water (many municipalities intentionally add phosphate compounds to help control corrosion in water distribution systems)
- Dirt and dust
- Leaves and grass
- Pollen
- Fertilizer runoff
- Rain carrying airborne debris
- Organic contamination
- Swimmers
- Detergent residue left on swimsuits and towels
Even some pool chemicals contribute phosphorus.
Many traditional metal sequestrants contain phosphates, phosphonates, or phosphonic-acid chemistry.
These products absolutely have value.
They keep metals dissolved in the water so they don’t stain plaster, tile, or other pool surfaces.
But here’s my problem.
They don’t actually remove the metals.
The metals stay in the water.
Eventually chlorine and ultraviolet light begin breaking those products down.
As they degrade, some of their phosphorus eventually becomes measurable orthophosphate.
Now you’ve added another algae nutrient.
Since the sequestrant continues breaking down, you have to keep adding more.
The metals remain.
You’re simply paying to keep them hidden.
That’s another example of solving one problem while creating another.
It’s one of the reasons I became such a believer in Culator Metal Eliminator.
Culator doesn’t hide metals.
It removes them from the water.
No continual chemical additions.
No secondary chemistry.
No new maintenance problems.
That’s elegant engineering.
I like products that subtract problems from a pool…
Not products that simply move them somewhere else.
A Little Wisdom About Testing Phosphates
Here’s something many pool owners—and even some professionals—don’t realize.
A pool can have a severe algae bloom…
…and still test surprisingly low for phosphates.
How is that possible?
Because living algae contains phosphorus.
Some of the phosphorus in your pool is tied up inside the algae itself.
When you test during an active algae bloom, that phosphorus isn’t always measured as dissolved orthophosphate.
Then you kill the algae.
The algae dies.
It begins decomposing.
Now some of that phosphorus is released back into the water.
Suddenly your phosphate test is much higher than it was before.
I’ve seen this happen many times.
People think the phosphate remover didn’t work.
In reality, the original test simply didn’t represent the pool’s total phosphorus load.
It’s another reminder that phosphate numbers should always be interpreted in context.
Traditional Liquid Phosphate Removers
Let’s be fair.
Traditional liquid phosphate removers work.
They remove phosphates.
My criticism has never been about whether they work.
It’s been about what happens while they work.
Most liquid phosphate removers use lanthanum chemistry.
The lanthanum reacts with dissolved orthophosphate and creates extremely fine insoluble particles.
Those particles become suspended throughout the water.
That’s why the pool often turns cloudy.
The cloudiness itself doesn’t necessarily tell you how high the phosphate level was.
The cloud is primarily the newly created insoluble particles, although other water conditions—such as calcium carbonate precipitation—can sometimes contribute to cloudiness as well.
Eventually those particles have to be removed from the pool.
Usually…
Your filter gets that job.
As the filter captures more and more of those particles, pressure begins to rise.
Flow begins to fall.
Turnover slows.
Circulation becomes less effective.
Sometimes dramatically.
If the filter isn’t cleaned in a timely manner, you’ve now weakened two of my Five Pillars…
Filtration…
and circulation.
As a weekly service company, this has always frustrated me.
We treat phosphates today.
The customer sees cloudy water tomorrow.
By next week’s visit the filter pressure has increased, circulation has slowed, and now we’ve created another maintenance issue that has to be addressed.
That’s not the kind of trade I like making.
Not because phosphate removal isn’t valuable…
But because the treatment itself often created additional work, additional maintenance, and additional opportunities for something else to fall behind.
And that’s exactly why I began looking for something better.
A Better Way: Aluminum Sulfate (Alum)
Before I get to the product that changed my opinion, I want to mention another phosphate-removal method that deserves some respect.
Aluminum sulfate—better known as alum—has been used in water treatment for decades.
Unlike traditional liquid phosphate removers that rely on your filter to remove the reaction products, alum works differently.
When properly applied, alum forms a heavy floc that captures phosphates and many other suspended contaminants. That floc settles to the bottom of the pool, where it can be carefully vacuumed directly to waste.
For the right situation, it’s an excellent option.
Instead of asking your filter to capture everything, you’re physically removing the contaminants from the pool.
That can significantly reduce the filter loading associated with traditional phosphate-removal treatments.
Of course, alum isn’t the right solution for every pool.
It requires proper water balance.
It requires patience while the floc settles.
It requires the ability to vacuum directly to waste without disturbing the settled material.
But when the situation is right, it’s another valuable tool in the toolbox.
Then I Found PhosLocker
This is where everything changed for me.
For years, my hesitation about phosphate removal wasn’t because I didn’t believe it worked.
It was because I didn’t like the side effects.
Now…
Those side effects are largely gone.
PhosLocker takes an entirely different approach.
Instead of pouring another chemical into the water…
It uses a replaceable pouch that simply sits inside your skimmer basket.
As water continuously flows through the pouch, the media captures phosphates from the water.
Nothing gets poured into the pool.
Nothing turns the water cloudy.
Nothing rapidly loads the filter.
Nothing causes filter pressure to spike because of the treatment itself.
Nothing intentionally reduces circulation.
Nothing intentionally reduces turnover.
Nothing creates another maintenance problem.
It simply removes phosphates.
That’s exactly the kind of engineering I appreciate.
Solve the original problem…
without creating another one.
That’s the kind of product I look for.
It’s the same reason I like Culator Metal Eliminator.
It removes metals instead of simply hiding them.
Now I have a phosphate remover that follows that same philosophy.
Why This Changes My Opinion
For years, people would ask me,
“Frank, should I remove phosphates?”
My answer was usually something like this:
“If you’re maintaining proper chlorine, good circulation, effective filtration, approximately 50 ppm borates, and staying ahead of the Five Pillars, phosphates move way down my list of concerns.”
I still believe that.
None of that has changed.
What has changed…
…is the tool.
I don’t have to choose between removing phosphates and creating another maintenance problem.
Now I can reduce algae’s food source without intentionally creating cloudy water, overloading the filter, reducing circulation, or increasing maintenance.
That changes the equation.
Now phosphate removal becomes another layer of protection.
Not because phosphates suddenly became my biggest concern…
But because I finally have a way to remove them that fits my maintenance philosophy.
Another Product That Has My Attention: PhosLocker Dual
There’s another product from PhosLocker that I think deserves mentioning.
It’s called PhosLocker Dual.
This product combines phosphate removal with a biological process designed to gradually biodegrade cyanuric acid (CYA).
If you’ve followed me for very long, you already know CYA management is one of the biggest challenges in residential swimming pools.
Too much CYA is one of the biggest reasons chlorine struggles to stay ahead of algae.
That’s why this product immediately caught my attention.
Instead of addressing only phosphates, PhosLocker Dual is designed to tackle two common pool problems at the same time.
It removes phosphates…
while gradually reducing CYA through biodegradation.
This isn’t intended to replace a major water exchange when CYA is extremely high.
It’s a gradual process that works while the pool continues normal operation.
If you’re dealing with elevated CYA from years of stabilized chlorine use and you also want to reduce phosphates, having one product address both issues is a very interesting concept.
We’re currently evaluating PhosLocker Dual across a variety of our own pools.
Everything we’ve seen so far has been very encouraging.
As always, I don’t recommend products simply because a manufacturer makes a claim.
Products earn my recommendation through real-world performance.
We’ll continue collecting long-term data.
But based on what we’ve seen so far, I believe PhosLocker Dual has the potential to become another valuable tool for both homeowners and professional service companies.
My Opinion Has Changed
People sometimes ask me,
“So…have you changed your opinion about phosphates?”
Yes.
And no.
I’ve never been against removing phosphates.
I’ve been against creating unnecessary maintenance problems while removing them.
That’s a very different position.
Traditional phosphate removers always forced me to weigh the benefit against the side effects.
Now I don’t have to make that trade nearly as often.
With PhosLocker, I can reduce one of algae’s biggest advantages…
without intentionally creating another maintenance headache.
That makes phosphate removal much more attractive.
Will we use PhosLocker on every pool?
Maybe.
We’re still gathering long-term experience.
But I can tell you this…
We’ll definitely be using it on many more of our pools than we ever would have with traditional phosphate removers.
In fact, it’s entirely possible it becomes part of our standard maintenance program.
Not because phosphates suddenly became my biggest concern…
But because removing them has become significantly easier.
If I can safely reduce algae’s food source…
Reduce maintenance headaches…
Reduce filter loading…
Reduce customer complaints about cloudy water…
And potentially reduce future chemical costs associated with algae recovery…
Why wouldn’t I?
That simply stacks the odds a little more in my favor.
And I’ll take every legitimate advantage I can get.
Where to Buy PhosLocker
PhosLocker is beginning to appear at select local pool stores, although it isn’t widely available yet.
If your local dealer doesn’t carry it, you can order directly from PhosLocker.com.
Use coupon code DEEPEND10 to save 10% on your purchase.
That same discount also applies through the professional shopping portal.
If you’re a pool professional, my recommendation is simple.
Order a few.
Try them on different pools.
Use them on pools with recurring algae problems.
Use them on difficult saltwater pools.
Use them on pools with heavy environmental loads.
Use them on pools that have always been difficult to keep ahead of.
See what you think.
Everything I’ve seen so far tells me this product is a genuine step forward.
I don’t hand out endorsements very often.
Products earn them by making my life easier, making my technicians’ jobs easier, and helping my customers have better pools.
So far…
PhosLocker has done exactly that.
Final Thoughts
I’ve said it for years.
I don’t like trading problems.
I like solving them.
That philosophy hasn’t changed.
What’s changed…
…is that I finally have a phosphate-removal product that fits that philosophy.
Phosphates don’t cause algae.
They fund it.
Your primary job is still to make sure chlorine wins the race.
Maintain the proper FC ratio.
Maintain your borates if you choose to use them.
Maintain reasonable pH.
Stay ahead of the Five Pillars.
Those things will always be the foundation of successful pool care.
But if you can also remove algae’s food source…
Without clouding the water…
Without overloading the filter…
Without sacrificing circulation…
Without creating another maintenance problem…
Then you’ve made the race even easier to win.
That’s why I believe phosphate removal has become a much more valuable tool than it was just a few years ago.
Not because the chemistry changed.
The technology did.
And sometimes the best innovations aren’t the ones that do something completely new.
Sometimes they’re the ones that finally solve an old problem…
without creating a new one.
That’s exactly what I believe PhosLocker has accomplished.