Reef Tank Week by Week Beginner Guide: 12-Week Startup

The first three months of a reef are a sequence, not a sprint. This reef tank week by week beginner guide from Gensou Aquascaping at 5 Everton Park lays out a twelve-week roadmap for SG beginners building a nano or mid-size reef. Two decades of local setups have shown us that the reefers who treat weeks one through twelve as a linear protocol — not a race — are the ones still enjoying the tank at year three.

Week 1 — Build and Fill

Position the tank and stand level on a properly rated base (HDB floor load calculations matter for tanks above 200 kg wet weight). Install sump, plumbing, return pump, skimmer and chiller. Rinse aragonite sand in RODI only; never tap. Add dry rock dry, aquascape first, then fill with pre-mixed saltwater at 1.025 SG, 25°C. Power everything up. No livestock yet.

Week 2 — Kick the Cycle

Dose ammonia to 2 ppm using Dr Tim’s One & Only or Fritz Turbo 900 (SGD 45-60 locally) plus pure ammonium chloride. Test ammonia and nitrite daily. Leave the skimmer off initially — the bacteria need the ammonia. Chiller on, lights low or off for the first two weeks to suppress nuisance algae. Expect nitrite to spike by day 10.

Week 3 — Cycle Progressing

Ammonia typically drops to zero by day 14-18. Nitrite still reading high. Keep testing daily. Do not add livestock yet — nitrite is toxic. Turn the skimmer on lightly at end of week three. Start running carbon passively (SGD 35/bottle) to clear any tannins or film. Test phosphate once as baseline.

Week 4 — First Cleanup Crew

Both ammonia and nitrite should now read zero for three consecutive days. Perform a 20 per cent water change to knock down the accumulated nitrate from the cycle. Add a modest cleanup crew — five Trochus snails, three Nassarius, two peppermint shrimp (SGD 80-120 total). No fish yet. Lights on at 30 per cent, six hours per day. Ugly stage begins — diatoms, cyano patches, light film. Normal.

Week 5 — First Pair of Fish

Add a tank-bred ocellaris clownfish pair (SGD 40-80) as the first fish. Acclimate over 30-45 minutes. Feed a pinch once daily for the first three days, then twice daily. Watch breathing and appetite. Test ammonia daily for a week to confirm the biofilter handles the new load. Water change 10 per cent at week-end.

Week 6 — Build Parameter Log

Begin weekly Sunday testing — alkalinity, calcium, magnesium, nitrate, phosphate. Log every reading. Diatoms should be receding; cyano may persist. Address flow dead spots by adjusting powerhead angles. The ugly stage is natural; avoid the urge to dose algaecides. Add a second fish if ammonia is stable — yellow watchman goby or firefish (SGD 25-60).

Week 7 — First Easy Corals

Introduce two or three easy-care soft corals: green star polyps, Kenya tree, pulsing xenia, a small zoa frag (SGD 20-60 each at Iwarna, Pinnacle or Carousell). Dip all frags in Coral RX or ReVive (SGD 35 per bottle) for five minutes before placement. Position mid to low in the tank. Run alkalinity at 8 dKH steady.

Week 8 — Assess Nutrients

Two months in, nitrate and phosphate reveal your feeding and skimming balance. Target 2-10 ppm nitrate and 0.03-0.08 ppm phosphate. Too low — feed more or skim less. Too high — cut feeding or add GFO (SGD 25/kg). Start building a refugium with a chaeto starter (SGD 10-15 swap from local reefer). Reverse-cycle the refugium light for night pH support.

Week 9 — LPS Introduction

With soft corals thriving, add your first LPS — a frogspawn, hammer, duncan or candy cane (SGD 45-120 each). LPS want stable alkalinity and moderate flow. Position on rock ledges, not in the sandbed. Start two-part dosing (Red Sea or BRS, SGD 55/3 L) to offset the uptick in calcium and alkalinity consumption. Test alk every other day during ramp.

Week 10-11 — Third and Fourth Fish

Add the third fish in week 10 and a fourth in week 11 — a peaceful six-line wrasse (SGD 45), royal gramma (SGD 35-50) or pair of firefish. Quarantine for 30 days in a separate QT tank if possible; if not, observe closely and treat with tank transfer method if ich appears. Corals should show visible growth by now — GSP mats extending, frogspawn fleshy, zoas opening wide.

Week 12 — Settling In

By week twelve, the system runs on rhythm. Weekly 10 per cent water changes, Sunday testing, daily parameter log, twice-weekly glass clean, monthly skimmer breakdown. Consider your first SPS frag — a montipora or birdsnest (SGD 40-80) — only if alkalinity and nutrients have held steady for three weeks. A disciplined reef tank week by week beginner guide approach delivers a healthy, colourful, parameter-stable reef at month three, and SG reefers who honour the twelve-week arc skip the common six-month crashes that send novices back to freshwater.

Related Reading

• Reef Tank First Month Routine Guide
• Reef Tank Budget Beginner Guide
• Reef Tank Parameters Beginner Guide
• Reef Tank Maintenance Schedule Guide
• Saltwater Aquarium Beginner Complete Guide