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Will A Sand Filter Remove Iron From Pool Water? How It Works

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Tim Rhodes

Have you ever asked the question – will a sand filter remove iron from pool water?

Let’s imagine the following situation: someone is tempting you to enter the pool and spend some time there.

You say yes, but after you ask a few questions you realize that there’s a possibility that your nails and hair will become stained.

Would you still get in the pool by simply ignoring that fact?

Did you ever think about what could cause the problems? 

The answer is simple: It’s the presence of the iron.

Let’s take some time to talk about those potential issues and after that, I’ll explain how you can use a sand filter to remove iron from pool water.


Is There Any Impact?

The stains can be a pretty big problem.

This can be caused if you have more iron concentration in the pool than the acceptable quantity.

Let’s be honest here; discoloration of the skin is something that no one likes to see.

If the water has changed the color it will bother the swimmers, some more, some less, but no one will like that.

The pool equipment will rust if you have an unbalanced level of iron concentration. 

As you know, any metal accessories (pump, pipes, ladders, and similar things) in the pool are corrosive and they will suffer the most because of this.

This is another reason why you should deal with the iron as soon as possible.

How Did I End Up With The Iron In My Pool?

There are many metals in the crust of the earth and iron is the 4th most common out there.

The metal will shine in a stunning silver shade but when it’s exposed to water or moisture it reacts with the oxygen which causes iron oxidation. 

The beautiful silver-colored metal is exposed to water and air and because of that, the corrosion process starts.

Iron is usually found in the water supply when the source is a well that might have iron metal in its ion state.

Once we purify the water, any metals will be deposited mostly in the pipe as well as the plumbing system until they enter the pool.

What happens now? 

It progressively destroys the pipes and other pool equipment through which it passes. 

On the other hand, it releases copper into the pool water.

If you believe that low-priced pool gear is going to do the job you might want to rethink it. 

Is There a Way To Identify The Iron Presence In My Pool?

The most common way is to take a sample of your pool water to the nearest pool store and get it checked for iron.

Also, remember to keep in mind that this isn’t necessarily the same thing.

This seems to be usually true in most cases. 

However, when you start testing the water you might be surprised when you get to another result. 

So please don’t make any conclusion before you have tested it.

With that being said, if the iron was indeed present in the pool at normal levels it’s quite hard to identify. 

However, as the concentration is increased the water begins to discolor in rusty brown. 

It can sometimes turn into some kind of bright green. 

Undoubtedly, swimming pools filled with this kind of water will just not please the swimmers.

Can I Remove The Iron From My Pool?

Yes, you can. 

It’s hard to handle a calcium-rich pool where you’ll have to drain all the water and proceed again by getting water from another source. 

Nevertheless, if the pool water is heavy in iron you should take care of it.

The Pool industry provides an iron remover that works efficiently to high the amount of iron in your pool waters. 

For certain instances, the pool will suffer from high levels of iron whenever the water source is well. 

And, in these situations, you should apply an iron remover when it starts to fill up with well water.

The chelating agent is going to deactivate the metal.

Sand Filter – One Of The Best Options Available

Method And Installation Description

We use sand filtering to eliminate suspended matter and also for floating and sinkable pieces.

The water is falling vertically, passing through a gravel bed or fine sand. 

Particles are extracted by absorption or by direct encapsulation. 

In case that there is an excessive loss of pressure on a filter then it should be rinsed.

A distinction needs to be made among persistent and discontinuous filtering. 

In continuous filtering (often upstream filters), the contaminated sand is continuously collected, rinsed, and reused without affecting the ongoing filtration process. 

Discontinuous filters (often downstream filters) stop, and the rinse needs to take place in the reverse direction.

Water molecules are released onto the sandy bed to make it spin around. 

Filtered water is pumped through the filter bed throughout the opposite direction. 

The toxic matter is released and runs together with the rinse water. 

The filtering water process can then be resumed.

The sand filter yield is based on two sand filtration processes (features), namely ground filtration as well as depth filtering. 

Surface filtering involves the collection of particles just above the filter bed.

Together, those little particles form a macro-porous lump that can obtain new particles in a quite efficient manner. 

Depth filtering usually includes smaller particles that are far more difficult to gather and yet are bound by adsorption to sand particles. 

The surface filtration dirt is easier to extract throughout reversed rinsing compared to the depth filtration dirt.

Specific Benefits And Drawbacks

The most significant advantage of a sand filter seems to be a simple system that you can use in plenty of other cases to produce substantial yields. 

It’s possible to install the sand filter in different phases of water control-as a pretreatment process as both a side-stream filter and as a polishing filtration.

A sand filter usually provides a potential for using the effluent again.

Sometimes, you will need to apply chemicals if you’re looking to increase sand filter yields. 

There is a disadvantage using sand filtering.

Once you clean the sand filter the water will become highly polluted. 

We highly advise the disposal of this highly contaminated water.

A preliminary sedimentation step for heavily loaded wastewater (a lot of suspended and sinkable matter) is carried out to limit the load on the filter. 

That kind of approach helps to avoid repetitive filter re-rinses. 

When one of the filters is cleaned, noncontinuous sand filters are always located in parallel set-up to keep the whole thing running.


We use sand filters in many different sectors and methods in which extensive removal of suspended matter from the water is necessary. 

Areas in which sand filtering is carried out include the manufacturing of drinking water, pools, car washes, underground water treatment, RWZI, etc.

Examples of implementation:

  • Iron disposal from underground water using sand filtrating
  • The last wastewater purification, metal precipitation monitoring, and sedimentation to destroy residual traces of iron-based sludge
  • Final wastewater purification that’s created in the production of iron, steel, and non-ferrous alloys
  • Sand filtering can even be preceded by methods such as sedimentation, coagulation, and flotation
  • The wastewater purification process can contain sand-blasting grit and colored molecules, for example, at shipyards
  • You can even use it for the final purification (or before active iron filtration) to allow reusing
  • You can use it as a drain-water disinfectant (sand filter) in greenhouse horticulture

Environmental Concerns

During the re-rinse phase, you can expect to see an exceptional water flow that contains a significant quantity of waste material generating. 

You’ll need to treat or dispose of such a flaw and additional costs will also accompany it. 

In several cases, that very same rinse water could be put to much better use, rinse water from metal removal is the best option for chemical removal of phosphatization.

How Much Can It Cost?

The initial investment for a polyester sand filter of 12 m3 / h for a swimming pool (48 to 60 m3) is around 700$. 

Industrial continuous sand filters of 5 m2 or approximately 50 m3 / h cost around $60,000.

Operating costs are typically low due to their simplicity and limited options for upkeep.

Is The Sand Filtrating a Hard Process?

Sand filtration seems to be a relatively simple procedure. 

All you need to do is follow this simple guide and you’ll have no problems whatsoever.

Other Methods To Clean Your Pool From The Iron

You have a lot of solutions to remove iron as well as other metals that water contains and you should pick the best method only after analyzing your pool. 

To do this, you should get the pool water analyzed by a lab in the pool shop. 

Once the high concentrations of iron have been confirmed you can take their guide for a solution.

1. Shock Treatment Of The Pool 

There are 2 ways to do this procedure: either it’s a revelation based on chlorine, or as you probably guessed the revelation that’s not based on chlorine.

That’s because it’s essential to know a pool specialist to truly understand which of those treatment types you should choose and which one is best suited to your pool.

You need to follow up with a precise diagnosis when you have finished selecting the type of treatment for the pool. 

Your pool specialist is likely to tell you this once you consult with him. 

The objective of this clarification treatment is to liberate you from the iron.

It’s possible that you won’t be eligible to use first-hand shock therapy

We recommend that you go through the instructions to start using it on the label. 

You can read the instructions below. 

You’re going to have to treat your pool to shock. 

Shock therapy will start the oxidation process of iron metal in the water.

Once oxidized, the iron separates from the water and it’s going to settle down as rust in one spot. 

Now when the rust is already separated, eliminate it from the water inside the pool.

While you use shock therapy, your pool water runs for around 6 – 8 hours.

Clean the pool walls in case there’s iron so everything drops off and mixes with the clean water undergoing treatment.

2. Flocculent Method

The flocculent technique is a simple but efficient strategy which is fabulous if you want to get rid of the iron in your pool eventually. 

The whole method involves adding flocculant, a liquid substance into the water so it will gather the iron placing everything in one place.

You should be following the procedure below to make use of this method. 

So the first thing you must include in the process is changing the direction of a filtration system to enable a backflow. 

Estimate the amount of flocculent you’re supposed to insert into the water.

It’s also advised adding one-fifth of the gallon of flocculants per 5000 gallons of fresh water.

Adding some flocculant to the water is necessary as well. 

It’s going to mix up with your pool water and gather the iron. 

This somehow pushes the iron down at the bottom of the pool so that they’re both settled.

Wait until they reach the bottom. 

When they have settled down, pick them up.

3. Don’t Allow Oxidization

This process ensures that the metal doesn’t oxidize. 

Chelating agents should be attached to pool water. 

It will form an iron compound in the water. 

So how will you know if you succeeded in preventing metal from oxidizing? 

It’s easy. 

Once the agent forms, you can be sure that you stopped the oxidation process.

4. Remove The Iron

Please ensure the pump of the filter is turned on when trying to implement this method.

Prevent the water from chlorinating so that it’s level starts to drop.

When the chlorine concentration has reduced to zero, reduce the pH of your water in the pool and don’t forget to add the pH Reducer.

Sit tight until the pH reader shows 6.8 ppm. 

Measure the quantity of iron cleaner you need to add.

Place one-fifth of an iron remover for around 5000 gallons of water.

Let the water stay in the pool overnight.

When your pool water is finally ready, raise the pH level to around 7.5 ppm

The pool water is supposed to be back to normal already.

Please remember that there is still a difference between calcium-rich and iron-rich pool water. 

In case that your pool water is full of calcium, then it’ll be challenging to treat the water except if you choose to drain the water entirely. 

When the water has been removed you will be able to fill your pool with water from another source. 

You can still treat it in the situation of iron pool water.

How To Avoid The Recurring

Normally, the problem can recur is that you might not be in a place to determine a way of filling up the pool again. 

If something like that happens, don’t worry! 

There is no reason to despair. 

Add a chelating agent to the water daily

Those agents eliminate metal ions from the water by extracting the metal at the floor of the pool.

Where Is Iron Originated From And How Does It Show Up In Your Pool?

Iron is typically located in the water. 

If the source is a well, the iron alloy may well be in its ionic state. 

But when you purify the water the metals will accumulate from either the pipe or pipe system until it gets to the swimming pool.

If you think that the second pool equipment will do the job, I can assure you that you should rethink that. 

There is a reason for saying that. 

The cheaper ones are made of iron that will easily corrode down the road. 

As mentioned, the iron in your pool can cause multiple problems and you shouldn’t take it lightly. 

The best way to assure you that you removed iron from the pool is that you don’t try to save your money by buying the cheap gear. 

You’ll not regret spending money on it because it will be a good investment looking long-term.

Is Iron Toxic In Well Water?

Human anatomy requires iron to function properly, but metal like many substances is toxic at high doses. 

But let’s keep it simple; you can’t drink enough water to consume the harmful amounts of iron.

The Environmental Protection Agency believes that iron in water is a secondary contaminant that does not have an immediate impact on health. 

Is hot water iron dangerous? 

To be honest, it’s not going to make much difference to your well-being; it will probably cause costly damage as well as other difficulties.

Final Thoughts

To swim in the pool water with less iron is a pleasure and we hope that this article explained how a sand filter removes iron from pool water.

You feel safe and can be 100% sure that you’re swimming in free, clean, fresh water, and therefore have no reason to be afraid of getting contaminated. 

Still, if you ever start to believe that the pool water has an increased iron level have it checked in a pool shop. 

The pool specialists will notify you of the processes involved and direct you properly once it has been verified.

The article above has carefully described the measures taken to extract iron/copper from pool water. 

So, if you think that your pool water seems to be not quite the greenish-blue color it used to be, a sand filter will remove iron from pool water

Once a specific method has been used to successfully remove iron from the pool, return to normal pool maintenance activities as well as at the same time take steps to prevent a recurrence of the situation. 

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