Can You Convert a Salt Pool to Magnesium? A Step-by-Step Guide

Every Aussie pool owner knows the feeling: you’ve heard the hype about "mineral pools." Your mates are talking about how silky the water feels, the therapeutic benefits for sore muscles, and the crystal-clear look that rivals a tropical lagoon. But if you’re sitting on a standard saltwater setup, you’re probably asking the big question: Can you convert a salt pool to magnesium without ripping everything out and starting from scratch?

The short answer is: Yes, absolutely.

Converting your existing saltwater pool to a magnesium mineral system is typically a retrofit process, not a renovation. It’s one of the most effective upgrades you can make for your backyard oasis. However, it’s not just about dumping a bag of minerals into the water. It requires balancing Total Dissolved Solids (TDS), potentially upgrading your filtration media, and recalibrating your equipment.

In this guide, we’ll walk you through the costs, the equipment checks, and the exact steps to successfully convert your salt pool to magnesium.

Is Converting Worth the Cost? Salt vs. Magnesium Maintenance

Before you commit to the switch, it’s crucial to understand what you’re signing up for. While we’ve covered the deep-dive into health perks in our article on The Truth About Magnesium Pools, here we focus purely on the practical side: maintenance and running costs.

Magnesium pools (often referred to as mineral pools) generally cost slightly more to set up initially due to the cost of the minerals compared to standard pool salt. However, many owners find the maintenance easier in the long run because magnesium is a natural flocculant—meaning it clumps debris together, helping your filter catch finer particles.

Here is a breakdown of how the two systems compare:

If you are still weighing up the pros and cons of the systems themselves, check out our detailed comparison: What Is a Mineral Pool System?

Pre-Conversion Checklist: What You Need Before You Start

Don't start draining water yet! To convert a salt pool to magnesium successfully, you need to ensure your current hardware is up to the task.

1. Check Your Chlorinator Compatibility

Most modern salt chlorinators are compatible with magnesium minerals. Magnesium chloride is essentially a type of salt. However, magnesium minerals have a different conductivity level than sodium chloride.

• Action: Check your manufacturer’s manual. You may need to adjust the output setting. Some older units might struggle to read the mineral levels correctly.

2. The Glass Media Upgrade

This is the step most DIYers miss. While you can use sand, leading mineral system manufacturers and industry experts strongly recommend switching from sand to glass filtration media.

• Why? Glass media provides a much finer filtration rate (capturing smaller particles) and prevents the magnesium from "clumping" inside the filter, which can happen with old sand.

3. Test Your TDS (Total Dissolved Solids)

You cannot simply add magnesium on top of a high-salt pool. If your current salt level is above 4,000 ppm, the water might become "oversaturated" when you add minerals, leading to cloudiness or equipment strain.

How to Convert Salt Pool to Magnesium in 5 Steps

Ready to make the switch? Follow this streamlined process to transform your pool water.

Step 1: Test and Lower TDS

Test your current salinity. If your salt levels are high (e.g., typical 4,000–6,000 ppm range), you will likely need to partially drain your pool to lower the sodium concentration.

• Target: You want to lower the water level enough so that when you refill with fresh water, the TDS is low enough to accept the new magnesium minerals without overshooting the recommended ppm (usually around 3,000–4,000 ppm depending on the brand).

Step 2: Swap the Filter Media

If you are using a sand filter, now is the time to replace the sand with coarse and fine glass media.

1. Turn off the pump and release pressure.
2. Scoop out the old sand (a wet/dry vac helps here).
3. Rinse the laterals carefully.
4. Fill with the recommended amount of glass media (glass is less dense than sand, so you usually need 10-20% less by weight).

Step 3: Add the Magnesium Minerals

Once your pool is refilled with fresh water and the filter is sorted, it’s time to add the magic.

• Dosage: Follow the instructions on the bag of your chosen mineral blend (e.g., Magnesium and Potassium).
• Method: Broadcast the minerals evenly across the pool surface while the pump is running. Do not dump them directly into the skimmer box.

Step 4: Adjust Chlorinator Settings

Since magnesium is more conductive than standard salt in some scenarios, or requires a different "set point," you may need to recalibrate your chlorinator. Reset the system so it learns the new water chemistry.

Step 5: Circulate and Balance

Run your filtration system for at least 24 hours to ensure the minerals are fully dissolved and circulated. Afterward, test your water chemistry again.

• Balance Check: Ensure your pH is within the range of 7.2 – 7.6. Magnesium pools tend to drift naturally higher in pH, so keep some acid on hand.

Warning: Always handle pool chemicals according to safety guidelines. SPASA recommends wearing protective gear when handling concentrated mineral salts.

Common Mistakes to Avoid During Conversion

• Overdosing the Pool: Adding too many minerals at once can cause scaling on your pool shell and equipment. It’s always easier to add more later than to dilute.
• Skipping the Glass Media: We mentioned it above, but it bears repeating. Sticking with dirty, old sand will significantly reduce the clarity benefits of your new magnesium system.
• Ignoring Cyanuric Acid (Stabiliser): When you drain water in Step 1, you lose stabiliser. Don't forget to test and top this up, or your chlorine will burn off instantly in the Aussie sun.

Maintenance & Cleaning: Is It Different from Salt Pools?

Once you have managed to convert your salt pool to magnesium, daily maintenance is surprisingly similar, but often easier. Because magnesium helps settle debris to the floor, you might find your water looks clearer, but you will still need to vacuum.

Can I Use a Robotic Cleaner?

Absolutely. In fact, robotic cleaners are ideal for mineral pools. Because magnesium water is "softer," it is less abrasive on the internal components of robotic cleaners compared to harsh, high-salt environments.

Aiper robotic cleaners, such as the Scuba series, are perfectly compatible with magnesium pools.

• Fine Filtration: Since magnesium clumps fine debris, using an Aiper robot with an ultra-fine filter basket ensures that this sediment is removed from the pool floor, reducing the load on your main sand/glass filter.
• Efficiency: The intelligent path planning ensures the robot covers the entire floor, scrubbing away any potential scale before it hardens.

FAQ about Magnesium Pool Conversion

Q: How much does it cost to convert a salt pool to magnesium?

A: In Australia, depending on the size of your pool, the initial conversion (including glass media and minerals) typically costs between $500 and $1,000 AUD. This is a fraction of the cost of installing a new system.

Q: Can I just add magnesium to my salt water pool without draining?

A: Technically, yes, you can add "maintenance" bags of magnesium to a salt pool. However, to get the full therapeutic benefits, you need a high concentration of magnesium. If your salt level is already high, adding more minerals will result in extremely high TDS, which can damage equipment. A partial drain is usually best.

Q: Will the water taste salty?

A: No. Magnesium pools usually run at a lower salinity level than traditional salt pools. While you might detect a faint taste, it is much milder and lacks the strong "ocean" bite of standard salt pools.

Final Thoughts

Deciding to convert your salt pool to magnesium is one of the best wellness investments you can make for your home. You get spa-quality water that is gentler on your skin, hair, and even your swimwear.

The process is straightforward: lower your old salt water, upgrade your filter media, and introduce the new minerals. With the right setup and a reliable robotic cleaner like the Aiper Scuba X1 Pro Max to handle the vacuuming, you’ll spend less time maintaining your pool and more time enjoying the therapeutic soak.