Reviews · Salt Mix
Best reef salt, ranked by what a gallon actually costs
Salt is the quiet recurring cost of reefing — and boxes lie by omission. A $75 box that mixes 200 gallons is cheaper salt than a $75 box that mixes 160. We rank every major mix by cost per mixed gallon, then split them into the two families that actually matter: elevated growth formulas vs near-natural-seawater baselines.
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How this ranking works: computed from box price ÷ manufacturer mix yield at reef salinity (~1.025), dataset updated 2026-07-01. Parameter families come from each maker's published water chemistry. Nobody pays for placement. Full methodology →
The picks
Want the ranking for your tank size and water-change schedule? The salt cost calculator computes your actual monthly spend for every salt here.
All 12 salts, cheapest per gallon first
| Salt | Family | Box | Mixes | Cost / gal |
|---|---|---|---|---|
| Instant Ocean Sea Salt | Growth (elevated) | $74.99 | 200 gal | $0.37 |
| Aquaforest Sea Salt | Natural / NSW | $89.99 | 200 gal | $0.45 |
| Kent Marine Sea Salt (Reef Blend) | Growth (elevated) | $89.99 | 200 gal | $0.45 |
| Instant Ocean Reef Crystals | Growth (elevated) | $74.99 | 160 gal | $0.47 |
| Fritz Aquatics RPM (Reef Pro Mix) | Growth (elevated) | $94.99 | 200 gal | $0.47 |
| Seachem Vibrant Sea | Natural / NSW | $79.99 | 160 gal | $0.50 |
| Aquaforest Reef Salt | Growth (elevated) | $99.99 | 200 gal | $0.50 |
| Brightwell Aquatics NeoMarine | Natural / NSW | $89.99 | 150 gal | $0.60 |
| Red Sea Red Sea Salt (Blue Bucket) | Natural / NSW | $119.99 | 200 gal | $0.60 |
| Red Sea Coral Pro Salt | Growth (elevated) | $109.99 | 175 gal | $0.63 |
| Tropic Marin Classic Sea Salt | Natural / NSW | $159.99 | 200 gal | $0.80 |
| Tropic Marin Pro Reef Salt | Growth (elevated) | $181.99 | 200 gal | $0.91 |
Prices are street prices at the dataset date and move with sales — the per-gallon ordering is much more stable than the absolute numbers.
Growth formula or natural parameters?
Elevated formulas (Reef Crystals, Coral Pro, RPM, Aquaforest Reef Salt…) mix high on alkalinity, calcium and magnesium so water changes themselves replenish what corals consume — a real convenience on stony-coral tanks that don't dose. The catch: on a tank that does dose, or does small changes, elevated alk swings parameters on every change.
Natural-parameter salts (Blue Bucket, Tropic Marin Classic, NeoMarine…) mix near natural seawater. They're the stable choice for tanks that dose to their own targets, and for sensitive SPS systems where a 3-dKH jump on water-change day is exactly what you're trying to avoid.
Neither family is "better" — the mistake is paying the elevated premium and then dosing anyway, or running a no-dose stony tank on a baseline salt and wondering where the alkalinity went. Pair the salt with how you actually run the tank; our dosing calculator covers the other half of that equation.
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