Equipment essentials: what your first reef tank actually needs

Reef equipment is its own consumer category, with reviews, holy wars, and brand loyalties. For your first tank, here's the actual hierarchy.

Must have on day one

• Tank — 20–40 gallons is a good first-tank range. Smaller is harder, not easier.
• Light — full-spectrum LED. AquaIllumination Hydra, Kessil, or Reefi for SPS-capable; cheaper LEDs are fine if you're not chasing SPS.
• Heater — titanium, with a controller (Inkbird is fine and cheap).
• Powerheads — at least one. AI Nero or MP10 if you can afford; Hygger / cheaper alternatives if you can't.
• Return pump — if you have a sump.
• RO/DI unit — non-negotiable. Tap water will fight you forever.
• Refractometer — for accurate salinity measurement. Hydrometers lie.
• Salt mix — Tropic Marin, Red Sea Coral Pro, or Instant Ocean Reef Crystals.
• Test kits — ammonia, nitrite, nitrate at minimum during cycle. Add alk, calcium, magnesium when corals arrive.

Worth adding within the first 6 months

• Protein skimmer — exports dissolved organics. Quality difference vs. budget is significant; buy decent.
• ATO (auto top-off) — saves you from daily topping off and parameter swings.
• Filter sock or roller — mechanical filtration; rolls win on convenience.

What you don't need (yet)

• Calcium reactor
• Algae scrubber
• pH probe / monitoring controller
• Dosing pumps
• Wave maker controller

These are all valid, but every one of them solves a problem you don't have at month one. Buy them when you have the problem, not before.

The gear-buying rule

Reef equipment compounds. The protein skimmer that's "fine" for your 30-gallon tank is undersized for the 90-gallon you'll inevitably want in two years. When in doubt, buy one size up — but never let perfect-future-gear stop you from starting today with adequate-current-gear.