How much
How much light for a 20 gallon high?
Pre-calculated for the 20 gallon high (24 × 12 × 16 in · water volume ≈ 16 US gal).
By scenario
| Scenario | Amount |
|---|---|
| SPS-dominant reef | 200–400 µmol/m²/s PAR ~25 W of modern reef LED. Examples: AI Hydra 32/64, Radion XR15 Pro G6, Reefi UNO/Lumi. |
| Mixed reef (LPS + some SPS) | 75–150 µmol/m²/s PAR ~16 W LED. Examples: AI Prime 16HD, Kessil A360X, Reefi UNO Black. |
| Softie / zoa / mushroom tank | 50–150 µmol/m²/s PAR ~10 W LED — softies often color up better at lower PAR. |
| Fish-only with live rock (FOWLR) | Any visible white light Aesthetic only. Hobby AC LED strips at $50–100 are fine. |
Brands hobbyists actually use
PAR-by-PAR ranked. Pick by tank footprint and the coral mix you'll keep.
AI Prime 16HD
Best small-tank reef light. Up to 24×24 in coverage for LPS/mixed.
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AI Hydra 32HD
Standard SPS-grade fixture. 24×24 in footprint at SPS PAR.
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Kessil A360X Tuna Blue
Pendant-style. Best 'shimmer' in the hobby. 24×24 in coverage.
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EcoTech Marine Radion XR15 Pro G6
Best programmable channel control. 24×24 in SPS-grade.
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