Magnesium Pool Conversion Cost and Payback in Australia

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A magnesium pool conversion costs about $2,930–$4,063 in parts for a 50,000 litre chlorine pool: a mineral-rated chlorinator at $2,299.99–$2,699.99 plus 15–22 ten-kilo bags of minerals, retailer prices read 10 October 2026. Converting a salt pool is cheaper upfront but never pays back: mineral top-ups cost $93–$240 a year more than salt.

The short answer

From liquid chlorine: $2,929.99–$4,062.89 in parts for 50,000 litres. One retailer lists two mineral-rated chlorinators sized for that pool at $2,299.99 and $2,699.99; the first dose is 15 bags (one retailer's chart) to 22 bags (a pool-chemistry guide) at $42–$61.95 a bag.
Running it in Brisbane: $271–$672 a year, counting the chlorinator cell spread over its life, 262.8 kWh of cell power at Energex's 27.9744c, and mineral top-ups. Installation is extra.
The $913 line: below about $913 a year of bought chlorine, the conversion does not pay back inside a 4.6-year cell life even on the cheapest parts. On the dearest parts the line is about $1,562.
From salt: the chlorinator can often stay, but replacing the water you lose costs more in minerals. At 20% of the water a year, top-ups run $126–$273 against $33 of salt: $93–$240 a year more, with no saving to set against it.
Over one cell life that premium adds up to about $425–$2,188 on a 50,000 litre pool.

Magnesium conversion payback for a 50,000 litre liquid-chlorine pool in Brisbane, by what you spend on chlorine now. Low case: $2,929.99 of parts and $271.24 a year to run. High case: $4,062.89 of parts and $672.19 a year. Installation excluded. Cell life at 6 hours a day is 4.6–9.1 years (our arithmetic on retailer and maker figures read 10 October 2026)
What you spend on chlorine now	Net saving a year, low case	Payback, low case	Net saving a year, high case	Payback, high case
$500 a year on chlorine now	$229	12.8 years, after the first cell has worn out	−$172	Never: the mineral pool costs more to run
$800 a year on chlorine now	$529	5.5 years, inside a long-lived cell only	$128	31.8 years, after the first cell has worn out
$1,200 a year on chlorine now	$929	3.2 years, inside one short cell life	$528	7.7 years, inside a long-lived cell only
$1,500 a year on chlorine now	$1,229	2.4 years, inside one short cell life	$828	4.9 years, inside a long-lived cell only

How much does a magnesium pool conversion cost from liquid chlorine?

A pool you dose by hand with liquid chlorine has no chlorinator, so a magnesium conversion is two purchases: a chlorinator that is rated for minerals, and the first dose of minerals. Worked for 50,000 litres at retail prices read on 10 October 2026:

The chlorinator. One online retailer lists two units sized for a 50,000 litre pool that it says run on salt or magnesium: a 25 g/hr unit for pools up to 50,000 litres at $2,299.99, and a 35 g/hr unit for up to 70,000 litres at $2,699.99. The same retailer says other brands charge $1,500–$5,000 for a mineral model; that is its claim, not a price we read. Check the manual of any unit you are quoted for a mineral setting or a mineral salinity range.
The first dose. One retailer's chart says 15 ten-kilo bags for 50,000 litres starting from 0 ppm; a pool-chemistry guide says about 22 bags to reach 3,500–4,500 ppm. Two retailers say 10kg in 10,000 litres raises dissolved solids by about 850 ppm, so 15 bags gives about 2,550 ppm and 22 bags about 3,740. The charts disagree because they dose to different targets. Ten-kilo bags were $42, $50, $55 (on sale from $69.50) and $61.95 at four retailers: 15 × $42 = $630 to 22 × $61.95 = $1,362.90.

Parts total: $2,299.99 + $630 = $2,929.99, up to $2,699.99 + $1,362.90 = $4,062.89. The cell goes on the return line and the controller needs a power point, so ask for installation as its own line; we found no Australian installation price we would stand behind.

The quotable version: converting a 50,000 litre liquid-chlorine pool to magnesium costs about $2,930–$4,063 in parts before installation, and the minerals are up to a third of it.

Does a magnesium conversion pay for itself? The worked payback

We use the same one-cell payback test as is it worth converting a pool to saltwater: parts ÷ (what you spend on chlorine now − what the new system costs to run), checked against how long the first cell lasts. Here is what changes for magnesium.

Running cost, Brisbane, 50,000 litres:

Cell. One chlorinator maker says most cells last 10,000–20,000 hours, 4.6–9.1 years at 6 hours a day (how long a pool chlorinator lasts). One retailer lists genuine replacement cells at $655–$1,489, so $71.72–$326.09 a year.
Power. One maker's cell is rated at 20V DC and up to 6A, 120W. At 6 hours a day that is at most 262.8 kWh a year: $73.52 at Energex's 2026–27 default market offer of 27.9744c/kWh. In Sydney, on Ausgrid's 33.1372c, add $13.57.
Mineral top-ups. Minerals leave with water you lose to backwashing, splash-out and rain. If 20% of the water is replaced in a year, 20% of the dose goes with it: 3 bags at $42 ($126) to 4.4 bags at $61.95 ($272.58).

Total $271.24–$672.19 a year. The table above runs the payback. At $800 a year of chlorine, cheap parts pay back in 5.5 years and dear parts in 31.8. At $500, dear parts never pay back.

The $913 line: below about $913 a year of bought chlorine, converting a 50,000 litre pool to magnesium does not pay back inside a 4.6-year cell life even on the cheapest parts. On dear parts the line is about $1,562. Add up last year's chlorine receipts before you take a quote.

Converting my salt pool to magnesium: what it costs each year

If you already have a salt chlorinator, the one-off cost is smaller: the water to dilute the salt, the first mineral dose, and a new chlorinator only if yours cannot run minerals. That is itemised on the cost of a mineral pool system, and this page does not repeat it.

What that page leaves for here is payback, and the answer is that there is none in money. A salt pool and a magnesium pool use the same chlorinator, the same cell hours and the same power. The only running cost that changes is what you put back after you lose water, and minerals cost more than salt:

Salt: 20% of a 200 kg dose is 40 kg, two 20 kg bags at one retailer's $16.50, $33 a year.
Minerals: 20% of 15–22 bags is 3–4.4 bags at $42–$61.95, $126–$272.58 a year.

The difference, about $93–$240 a year, is what the change costs you every year for as long as you run minerals: about $425 over a short 4.6-year cell life on cheap bags, and about $2,188 over a 9.1-year life on dear ones. Lose more water than 20% a year and it is more.

That does not make it the wrong choice. The case for magnesium is how the water feels, and that is a preference rather than a saving; claims about skin benefits are vendor claims, and mineral pool vs saltwater pool sets out which claims we could and could not verify. The quotable version: switching a salt pool to magnesium has no payback, because the only running cost it changes is the refill, and minerals cost more than salt.

What moves a magnesium conversion quote in Queensland and elsewhere

Your chlorine spend. The single biggest input, and the one only you know.
Bag price and bag count. $42 against $61.95 a bag, and 15 against 22 bags, together move the first dose by $733.
Your electricity network. The cell's power is a small line: $73.52 a year on Energex, $87.08 on Ausgrid at the same hours.
Cell life and cell price. A long-lived cheap cell costs $71.72 a year; a short-lived dear one $326.09. Ask what a replacement cell costs for the model you are quoted.
Stone coping. Minerals are chloride salts like pool salt, so the sealing advice for sandstone and limestone around a salt pool applies; see pool coping cost.

If the conversion is part of a wider equipment refresh, put the chlorinator model, its mineral rating and the cell price in writing, then compare pool quotes on the same specification. Listed pool businesses cover Brisbane and Sydney.

Common questions

How much does a magnesium pool conversion cost?

For a 50,000 litre pool on liquid chlorine, about $2,930–$4,063 in parts at retail on 10 October 2026: a mineral-rated chlorinator at $2,299.99–$2,699.99 and 15–22 ten-kilo bags of minerals at $42–$61.95. Installation is extra. From an existing salt pool it is cheaper, often minerals and water only.

How much does a magnesium pool conversion cost in Queensland?

The parts are priced nationally online, so the same $2,930–$4,063 for a 50,000 litre chlorine pool. What is local is the power: the cell's 262.8 kWh a year costs $73.52 at Energex's 27.9744c on the AER 2026–27 default market offer.

Is converting to a magnesium pool worth it?

In money, only from liquid chlorine and only if you spend enough on it. In our Brisbane example the conversion does not pay back inside a 4.6-year cell life below about $913 a year of chlorine. From salt it never pays back: minerals cost $93–$240 a year more.

How many bags of minerals does a 50,000 litre pool need?

From fresh water, 15 ten-kilo bags on one retailer's chart and about 22 on a pool-chemistry guide. At about 850 ppm per 10kg in 10,000 litres, those reach roughly 2,550 and 3,740 ppm.

Are magnesium pools more expensive to run than salt?

Yes, by the cost of the refill. If 20% of a 50,000 litre pool's water is replaced in a year, salt top-ups cost about $33 and mineral top-ups $126–$273 at retail prices read 10 October 2026.

Sources

General information only, current at 2026-10-10. Pool rules differ by state and by council, and penalty amounts are updated regularly. Confirm your own obligations with your council or a registered inspector before acting.