Three current salt routes
| Salt | Pack | Checked price | Published yield | Decision note |
|---|---|---|---|---|
| D-D H2Ocean Classic Pro | 23 kg | £69.99 | 592–702 L | 35 ppt is the suggested reef target; designed around regular water changes |
| Red Sea Coral Pro | 22 kg | £74.99 | up to 660 L | 37.1 g/L at 34 ppt or 38.2 g/L at 35 ppt; higher-alkalinity profile |
| Tropic Marin Pro Reef | 25 kg | £85.95 | Check the bucket label | Lower-buffering profile; retailer listings describe roughly 7–8 dKH |
The reliable mixing workflow
- Make RODI first. Use final DI-polished water and record the TDS reading.
- Use a clean, dedicated container. Keep salt and equipment away from detergents, metals and household residue.
- Set the temperature. Bring the water close to the manufacturer's reference temperature, commonly around 24–25°C.
- Weigh the salt. Start with the label's grams-per-litre instruction for your target salinity. Do not assume 35 g/L works for every brand.
- Add salt to water slowly. Run a small pump for circulation; avoid dumping a dry pile into one corner.
- Mix until clear, then measure. Calibrate a seawater refractometer or use another appropriate salinity instrument. Adjust with salt or RODI in small steps.
- Match the replacement water. Temperature and salinity should be close to the aquarium before a water change.
Worked example: 20 litres at 35 ppt
Red Sea Coral Pro's published dose for 35 ppt is 38.2 g/L. For 20 litres, the starting calculation is 20 × 38.2 = 764 g. Add that amount gradually, mix, measure and correct. The result is a starting calculation—not permission to skip the salinity check.
Mixing time and storage
Manufacturers differ. D-D says its H2Ocean salt is normally ready once clear after about 30 minutes and cautions against unnecessarily extended mixing. Red Sea's FAQ describes a controlled test mix and says not to aerate during that test. Aquaforest says freshly prepared water can be used once clear but recommends using dissolved salt within five days. Follow the exact salt's instructions instead of creating one universal rule.
Which salt should you choose?
Choose around your maintenance method, not marketing adjectives. A regular-water-change system may suit a balanced classic formula such as H2Ocean Classic Pro. A higher-alkalinity mix such as Coral Pro can suit a mixed reef or frag system, but it should be used consistently and monitored. Tropic Marin Pro Reef is positioned around a lower-buffering, stable reef profile. Switching salt can change alkalinity, calcium and magnesium, so test after the change.
Sources and limitations
Mixing and price examples were checked against D-D H2Ocean information, Red Sea's mixing FAQ, current Red Sea UK listings and a current Tropic Marin UK listing. We have not independently tested any salt batch.