Red Sea Salts - 10 kg (300 Ltr. Bag)
Pack size
10 kg bag
Cost per litre
$0.24
Water type
Marine + Reef
Red Sea Salts - 10 kg (300 Ltr. Bag)
One 10 kg bag mixes 300 litres of moderate-alkalinity reef seawater, at the cheapest cost per litre of our three Red Sea Salt pack sizes. Red Sea Salt is Red Sea's original marine salt mix, formulated to a natural, reef-stable alkalinity that suits fish-only systems and reef tanks run without heavy supplementation. This is the smallest pack size we stock – good for a nano or small display, or for trying the salt before committing to a bigger bag.
Key features
- Makes 300 litres – one 10 kg bag mixed to reef salinity (35 ppt), roughly six 50 L water changes.
- Moderate, reef-stable alkalinity – 7.7–8.1 dKH at 35 ppt, closer to natural seawater than the elevated alkalinity of Coral Pro Salt.
- Dissolves fast and clean, with no cloudy residue once fully circulated.
- Small enough to store in a cupboard rather than needing dedicated bucket space.
Specifications
| Pack weight | 10 kg |
|---|---|
| Makes | 300 L at reef salinity (35 ppt) |
| Alkalinity at 35 ppt | 7.7–8.1 dKH |
| Calcium at 35 ppt | 415–430 mg/L |
| Magnesium at 35 ppt | 1,230–1,290 mg/L |
| Potassium at 35 ppt | 375–395 mg/L |
| Format | Bag – decant into a sealed container |
Which pack size do I need?
We stock Red Sea Salt in three pack sizes. Cost per litre doesn't scale with pack size the way you'd expect, so it's worth checking the numbers rather than assuming bigger is cheaper:
| Pack | Makes |
|---|---|
| 10 kg bag (this listing) | 300 L |
| 25.2 kg bag | 750 L |
| 20 kg refill box | 600 L |
This 10 kg bag is currently the cheapest of the three per litre – a reasonable default if you don't already own a bucket to decant into and don't need the volume of the larger bag.
Dosage and directions
Mix into clean RO or RO/DI water with circulation until fully dissolved – allow around 20 minutes. Aerate before use, and match temperature and salinity to your display before adding. Use freshly mixed saltwater promptly rather than storing it mixed for extended periods.
Suitable for, and not suitable for
Suited to nano and small-to-medium systems, or as a starter bag before committing to the 25.2 kg bag on a larger tank. Reef tanks with heavy calcium and alkalinity demand from fast SPS growth are usually better matched to Red Sea's Coral Pro Salt, which mixes to a higher starting alkalinity and calcium level.
Care and maintenance
Store sealed and dry. Once opened, reseal firmly – moisture reaching the unmixed salt changes the effective mix ratio for later batches.
Warranty and delivery
Sold subject to Red Sea's standard product guarantees, which apply in addition to your consumer guarantee rights under Australian Consumer Law. Ships as a standard parcel.
Common questions
Why is the smallest bag the cheapest per litre?
Pack pricing doesn't always scale neatly with size – on our shelf right now, this 10 kg bag is priced lower per litre than either the 20 kg refill box or the 25.2 kg bag. Worth checking current pricing across all three before you buy, since this can change.
Is 300 litres enough for my tank?
For a nano or small system doing modest water changes, yes. For a larger display or a full water-change routine, the 25.2 kg bag will mean fewer repeat purchases.
What's the difference between this and Coral Pro Salt?
Red Sea Salt mixes to a moderate alkalinity, around 8 dKH, suited to fish-only tanks and naturally-run reefs. Coral Pro Salt mixes to a higher starting alkalinity and calcium level for reef tanks with heavier coral growth demand.
Does this bag come with a scoop?
No – see our Red Sea Salt Measuring Cup for consistent, repeatable dosing.
