Red Sea Coral Pro Sea Salts - 22 kg (660 Ltr) Bucket

• 660 litres from one purchase - about three months of weekly 10% changes on a 500 litre system, so you reorder four times a year instead of monthly.
• Screw-top resealable bucket - the format that survives a Queensland summer. Salt draws moisture from humid air, and an airtight bucket is the difference between a scoopable last third and a solid block.
• 11.5-12.5 dKH - carbonate headroom for a reef consuming alkalinity faster than a natural-seawater salt replaces it.
• Calcium 450-480 mg/L, magnesium 1350-1430 mg/L - lifted proportionally, so no single foundation element runs ahead of the other two.
• Potassium 385-415 mg/L - straddles Red Sea's 400 ppm reef target without separate dosing.
• Dissolves clear in about 20 minutes - the reformulated blend, which matters when you are mixing 50 litres at a time.
• Reusable bucket - most reefers end up using the empty as a mixing or change bucket.
• $0.27 per litre mixed - the lowest cost per litre in the Coral Pro range, cheaper than both the 7 kg bucket and the 20 kg refill box at current pricing.

All three packs are the identical formula. The choice is storage and turnover, not chemistry.

Buy the pack you will finish within roughly three months of opening. Beyond that, humidity starts to win.

Water change volume is what determines this, not tank size on its own. The figures below assume a 10% weekly change.

On systems under about 200 litres, a bucket this size will still be open in nine months. The 7 kg bucket is the better buy there, even though the litre-for-litre maths says otherwise.

1. Start with RO or RO/DI water at tank temperature, around 25 degrees C.
2. Add salt to water with a powerhead already running - never water to salt.
3. Work to roughly 1 kg per 30 litres, then check and adjust.
4. Circulate and aerate until completely clear, normally about 20 minutes.
5. Match temperature and salinity to the display before use.

Set the final salinity with a refractometer, not with the scoop. The 1 kg per 30 litre rating is Red Sea's pack figure; the precise dose that lands on 35 ppt shifts with source water and measuring method.

Mixed saltwater is best used within about 24 hours. Standing longer, alkalinity drifts down and carbonate precipitates onto the bottom of the drum.

Suitable for

• Larger mixed reefs, LPS and soft coral systems in active growth
• Frag and coral grow-out systems doing high-volume changes
• Reefers holding foundation levels by water change rather than by dosing
• Anyone mixing 40 litres or more at a time

Not suitable for

• Freshwater aquariums - this is full synthetic seawater, not a tonic or aquarium salt
• Mature SPS reefs held at 7-8 dKH, where a 12 dKH change swings alkalinity enough to burn tips. Red Sea Salt at 7.7-8.2 dKH matches those systems
• Nano and small systems - 660 litres will outlast its own shelf life in the bucket
• Evaporation top-up, which always uses fresh RO water only

Seal the lid fully after every scoop and keep the bucket off a bare concrete floor. Concrete wicks moisture, and this is the single most common reason a part-used bucket sets solid.

Clumped salt has not gone off, but the mass per scoop changes, so weigh it instead of measuring by volume. Break up any lumps before they go into the mixing drum.

• Red Sea Seawater Refractometer - the instrument that actually sets your salinity.
• Red Sea Reef Foundation Pro Multi Test Kit - verifies the calcium, alkalinity and magnesium your mixed water landed on.
• Coral Pro Salt 20 kg refill box - refills this bucket once it is empty.
• Coral Pro Salt 7 kg bucket - the size that suits a smaller system.
• Red Sea Coral Colours Pro Test Kit - covers the iodine, potassium and iron that water changes alone will not hold steady.

Salt is a consumable and carries no service warranty, but the consumer guarantees under Australian Consumer Law apply. A bucket that arrives split, contaminated or that will not dissolve is replaced.

At 22 kg this is a heavy freight item, so expect it to be handled separately from a small parcel order. Check the lid seal and the bucket wall on arrival before you open it.

How many litres does a 22 kg bucket of Coral Pro Salt make?

A 22 kg bucket of Red Sea Coral Pro Salt makes 660 litres of seawater at 35 ppt, which is Red Sea's pack rating of 1 kg per 30 litres. Set the final salinity with a refractometer, since the exact dose to reach 35 ppt varies with source water.

Is the 22 kg bucket better value than the 20 kg refill box?

Yes, on cost per litre. At current pricing the 22 kg bucket works out to $0.27 per litre, against $0.31 per litre for the 20 kg refill box - a case where the box, despite using less plastic, is not the cheaper buy. The bucket also gives you an airtight, reusable container, which the box does not.

My bucket has set solid - is the salt still usable?

Clumped salt is still chemically sound; it has absorbed atmospheric moisture, not degraded. Break the lumps up and weigh your dose rather than scooping by volume, because compacted salt is denser per scoop than loose salt.

Can I mix a full bucket of saltwater and store it?

Storing mixed saltwater beyond about 24 hours lets alkalinity drift down and carbonate precipitate out, so the water you use is not the water you mixed. Store the salt dry and mix each batch as you need it.

Will Coral Pro Salt raise the alkalinity in my tank?

On a system currently sitting at 7-8 dKH, changing water with 12 dKH salt will pull the tank upward over successive changes. That is the intent on a growing reef, but it should be approached gradually rather than with one large change.