Phase 1, Before the Tank Arrives

The decisions you make before the tank is in the room determine whether setup
day is straightforward or full of improvised fixes. Do this work first.

Choose and Prepare the Location

• Floor load capacity. A filled reef tank weighs approximately
  10 lbs per gallon, a 25-gallon tank fully set up weighs 250+ lbs. Confirm
  the floor where the tank will sit can support this load. Most modern homes
  handle this fine on concrete slabs or over joists. Very old homes or upper
  floors with visibly springy floors warrant checking with a contractor.
• Level surface. The tank stand must sit level, not close to
  level, exactly level. An unlevel tank creates uneven pressure on the glass
  seams and can cause a slow leak or catastrophic failure over months. Check
  with a bubble level in two directions before placing the stand.
• Away from direct sunlight. A tank in direct sunlight will
  have uncontrollable algae growth, temperature spikes from solar heat gain,
  and unpredictable parameter swings. No amount of equipment compensates for
  direct sun on the tank. Avoid windows without curtains or blinds that block
  afternoon sun.
• Away from heating and cooling vents. HVAC vents cause
  ambient temperature swings that translate directly to tank temperature
  instability. Position the tank away from ceiling or floor vents.
• Accessible on three sides. You will need to reach the
  inside of the tank for maintenance from the front and both sides. A tank
  pushed against two walls makes maintenance significantly harder over years.
• Electrical access. Count the outlets needed: return pump,
  wavemaker, heater, light, and potentially skimmer and ATO pump. A
  dedicated surge-protected power strip positioned near but not directly
  under the tank, water and electricity in the same space require caution.
  A “drip loop” on every cord (cord drapes below the outlet before going
  up to the equipment) prevents water from running down the cord into the outlet.

Purchase Everything Before Setup Day

Setting up with all equipment on hand is dramatically smoother than setting
up 80% of the tank and waiting for a missing part to arrive. Confirm you have:

• ☐ Tank and stand
• ☐ Lighting fixture and mount/arm
• ☐ Heater (sized correctly, 3–5 watts per gallon is the general rule)
• ☐ Return pump (if not included with AIO tank)
• ☐ Wavemaker or powerhead
• ☐ Reef-grade salt mix
• ☐ RODI water source (unit or purchased jugs)
• ☐ Refractometer and calibration solution
• ☐ Independent digital thermometer
• ☐ Test kits, ammonia, nitrite, nitrate at minimum
• ☐ Live rock or dry rock
• ☐ Aragonite sand (if using a sand bed)
• ☐ Bottled bacteria product (Dr. Tim’s One and Only or Fritz TurboStart 900)
• ☐ Raw unprocessed shrimp (from the grocery store, cycling ammonia source)
• ☐ Filter floss or filter socks
• ☐ Activated carbon in a media bag
• ☐ Mixing container for saltwater (5+ gallon bucket or dedicated mixing station)
• ☐ Small powerhead or airstone for mixing saltwater
• ☐ Siphon tube for water changes
• ☐ Log, notebook or spreadsheet template ready
• ☐ Nitrile gloves (for reef maintenance)
• ☐ Magnetic glass cleaner

Phase 1 Verification

• ☐ Tank location confirmed: level, no direct sunlight, away from vents
• ☐ All equipment purchased and on hand
• ☐ RODI water source confirmed and tested (TDS under 5 ppm)
• ☐ Electrical plan confirmed, adequate outlets, drip loops planned

Phase 2, Tank Placement and Stand Setup

Position the Stand

• Place the stand in its final position before anything goes in or on it, a filled tank cannot be safely moved.
• Level the stand with a bubble level in two directions (front-to-back and side-to-side). Most stands have adjustable feet, use them until the bubble is centered.
• If the stand has cabinet doors, confirm they open fully without hitting walls or other furniture.

Place the Tank

• Most glass tanks require a foam mat between the tank bottom and the stand surface, this distributes pressure evenly and prevents stress fractures from minor stand irregularities. Check whether your tank or stand includes one; add a 1/4″ foam sheet if not.
• Place the tank on the stand with two people. Inspect the tank before filling, check all seams for cracks, check the bottom glass for chips or stress marks. Reject any tank with visible seam irregularities before water goes in.
• Re-check level with the tank on the stand. Even a stand that read level before can shift slightly under the tank weight.

Phase 2 Verification

• ☐ Stand is level in both directions, bubble centered on both axes
• ☐ Foam mat placed between stand and tank (if required)
• ☐ Tank inspected for seam cracks and glass damage, none found
• ☐ Tank is in final position, it will not be moved once filled

Phase 3, Mix Saltwater

Mix saltwater before adding anything to the tank. This gives it time to
fully dissolve and aerate and allows you to verify salinity before it touches
your rock or sand.

Mixing Process

1. Fill your mixing container with RODI water. Verify TDS reads under 5 ppm, if higher, check RODI membranes and DI resin.
2. Add reef-grade salt mix slowly to the circulating water, follow the manufacturer’s starting ratio, then adjust based on your refractometer reading. Most reef salts mix at approximately 1/2 cup per gallon to reach 1.025, but verify with your specific brand’s instructions.
3. Run a small powerhead or airstone in the mixing container to circulate and aerate the water as the salt dissolves. Allow to mix for a minimum of 30–60 minutes before testing.
4. Test salinity with the refractometer. Target: 1.025–1.026 SG. Adjust by adding more salt (to raise) or more RODI water (to lower) in small increments, allowing time to mix between each adjustment.
5. Check temperature of the mixed saltwater, it should be close to the tank’s planned operating temperature (77–79°F). Cold water dissolves salt more slowly and reads slightly higher on the refractometer.

Calibrating the Refractometer

Before using the refractometer: place 2–3 drops of RODI water on the prism
and adjust the calibration screw until the boundary line reads exactly 1.000
(or 0 ppt on the salinity scale). Wipe clean and test your saltwater. Do this
every session, refractometers drift and room temperature affects the reading.

Phase 3 Verification

• ☐ RODI water TDS confirmed under 5 ppm
• ☐ Refractometer calibrated with RODI water
• ☐ Mixed saltwater reads 1.025–1.026 SG
• ☐ Saltwater mixed for at least 30–60 minutes and fully dissolved

Phase 4, Add Sand and Aquascape Rock

Sand and rock go in before water. Aquascaping a tank that’s already filled
is extremely difficult, do this work dry.

Sand (If Using)

• Use aragonite sand, the calcium carbonate composition provides alkalinity buffering and is the biologically appropriate substrate for a reef tank.
• Depth: 1–2 inches for most beginner setups. Enough depth to allow burrowing fish and invertebrates to dig, but not so deep that anaerobic zones develop in the deep sand bed and release hydrogen sulfide during disturbance.
• Rinse bagged sand under RODI water before adding to the tank, even “pre-washed” sand releases a significant amount of fine dust that clouds the water. Rinse until the water running off the sand is mostly clear.
• Add sand to the dry tank before rock. Spreading it evenly before the rockwork is placed allows the rock to be positioned with the sand settled around its base.

Aquascaping

The aquascape is the structural foundation of the tank, it determines flow
patterns, available coral placement, fish territory, and visual appeal. Plan
it before you start placing rock and execute it deliberately.

• Stability first. Every rock structure must be physically stable, able to withstand a direct hit from a wavemaker blast or a curious fish without toppling. A rockfall in a tank with livestock can crush corals, injure fish, and crash parameters from the organic material disturbed.
• Secure key rocks. Use reef-safe two-part epoxy putty to bond large or load-bearing rocks together at contact points. Allow to cure according to the product instructions before adding water.
• Leave open areas. Avoid filling the entire tank floor with rock. Open sand areas give fish territories, allow clean-up crew movement, and prevent detritus from accumulating in inaccessible dead spots.
• Create depth and dimension. A flat row of rocks across the back is less interesting and less functional than a tiered structure with caves, overhangs, and varying heights. Overhangs give Royal Grammas and other cave-dwelling fish shelter and encourage natural behavior.
• Plan for coral placement. Where will mid-tank corals go? Upper tank? Think about PAR zones and flow patterns from your planned wavemaker position when deciding where to place flat ledges or branch structures that corals will eventually grow on.
• Keep rock 2–3 inches from the glass. Proximity to the glass creates dead spots with no flow, encourages detritus accumulation against the back and sides, and makes glass cleaning impossible in that area. Maintain clearance on all sides.

See: Live Rock in Reef Aquariums |
Reef Tank Sand Guide

Phase 4 Verification

• ☐ Sand added at 1–2 inch depth, rinsed before adding
• ☐ Rock aquascape complete and stable, all structures tested for stability by hand
• ☐ Key rocks secured with reef-safe epoxy where needed
• ☐ Open sand areas maintained
• ☐ Rock kept 2–3 inches from glass on all sides
• ☐ Aquascape visually assessed from front, satisfied with layout before filling

Phase 5, Fill the Tank and Install Equipment

Fill with Saltwater

• Pour mixed saltwater into the tank slowly to avoid disturbing the sand bed. Pour over the rock or place a plate on the sand and pour onto the plate, the plate disperses the flow and keeps the sand from clouding badly.
• Fill to the operating level (for AIO tanks: just below the overflow slots on the rear filtration chamber).
• The water will cloud significantly from sand disturbance during filling, this is normal and clears within 24–48 hours as the return pump runs and the sand settles.

Install and Position Equipment

• Heater: Position in a high-flow area of the tank where
  water flows past the temperature probe continuously. For AIO tanks, the
  second rear chamber (pump chamber) is typically the best location, water
  flows through it constantly and the heater is hidden from the display.
  Do not allow the heater to touch the glass or sand, mount it vertically
  or at a 45-degree angle using the included suction cup mounts.
• Return pump: Positioned at the bottom of the return chamber
  in AIO tanks. Prime it before turning on if required (check manufacturer
  instructions). Ensure the return line is directed to create broad,
  randomized flow across the tank surface, not aimed directly at the rockwork.
• Wavemaker: Mount on the side glass, mid to upper tank,
  aimed across the tank at a slight downward angle toward the front glass.
  This creates a circular flow pattern that carries water across the surface,
  down the front glass, across the bottom, and back. Adjust position after
  running for 24 hours to eliminate obvious dead spots.
• Lighting: Mount at the manufacturer’s recommended height
  above the water surface. Set intensity to 20–30% for the startup period, the tank doesn’t need full intensity during cycling and high intensity fuels
  algae growth on the new rock. Set the photoperiod: 10–12 hour schedule
  with 30–60 minute dawn and dusk ramps.
• Skimmer (if using): Install in the appropriate chamber
  or sump section according to the manufacturer’s water depth requirements.
  Do not run the skimmer at full output during cycling, turn it on but
  set it to produce minimal output during the first two weeks to avoid
  pulling out the bacteria product you’ve dosed.
• Filter floss: Place in the first rear chamber of an AIO
  tank (the mechanical filtration chamber). Cut to fit snugly so all water
  passes through the floss rather than around it.
• Activated carbon: Place in a media bag in the second
  or third chamber. Rinse the carbon under RODI water before placing to
  remove carbon dust.

Run Everything and Verify

1. Turn on the return pump. Confirm water is circulating through all filtration chambers and returning to the display tank. Listen for unusual noise, grinding or cavitation suggests air in the pump or an impeller issue.
2. Turn on the wavemaker. Confirm flow is reaching all areas of the tank, look for dead spots (areas where nothing is moving) and adjust position.
3. Turn on the heater. Confirm the indicator light is on. Check the independent thermometer and record the temperature every hour for the first 3 hours to confirm the heater is holding the target.
4. Turn on the light at minimum intensity. Confirm the schedule is programmed correctly.
5. Test salinity in the tank water 30 minutes after filling. Record the result. Target: 1.025–1.026.

Phase 5 Verification

• ☐ Tank filled with mixed saltwater, water cloudy but clearing
• ☐ All equipment installed and running
• ☐ Return pump circulating, no grinding or cavitation
• ☐ Wavemaker producing flow, no obvious dead spots
• ☐ Heater running, indicator light on
• ☐ Temperature confirmed on independent thermometer, target 77–79°F
• ☐ Salinity confirmed in tank water, 1.025–1.026
• ☐ Light running at 20–30% intensity on correct schedule
• ☐ Filter floss installed in mechanical chamber
• ☐ Activated carbon installed in media bag

Phase 6, Start the Nitrogen Cycle

The cycle begins the moment an ammonia source enters the tank. This phase
lasts 4–8 weeks. Nothing living goes into the tank during this time.

Day 1, Add Bacteria and Ammonia Source

• Dose bottled bacteria product, full dose for tank volume, added directly to the tank in a high-flow area. Do not run activated carbon or UV sterilization during cycling, both can remove or kill the bacteria.
• Place a grape-sized piece of raw, unprocessed shrimp directly into the tank on or near the rockwork. This will decompose over the coming weeks and provide continuous ammonia for the cycling bacteria.
• Record Day 1 in the log: date, salinity, temperature, and “cycle started.”

Days 3–42, Test and Log

• Test ammonia and nitrite every 2–3 days. Record every result in the log with the date.
• Do not perform water changes during the cycle unless ammonia or nitrite exceeds 8 ppm.
• Do not add anything to the tank, no livestock, no food, no additional chemicals.
• Do not adjust equipment settings, let the tank run at consistent baseline conditions.

Cycle Completion Criteria

• Ammonia reads 0 ppm on two consecutive tests taken 24 hours apart
• Nitrite reads 0 ppm on the same two consecutive tests
• Nitrate is detectable (confirms the full cycle ran)

Post-Cycle Water Change

• When cycle completion criteria are met: remove the shrimp from the tank.
• Perform a 30–50% water change with freshly mixed RODI saltwater at matching temperature and salinity.
• Target post-water-change nitrate: under 20 ppm (under 10 ppm if corals will be added within the first few months).
• Wait 24 hours after the water change and retest ammonia and nitrite. Both must still read 0 ppm. If they do, the cycle is confirmed stable.

See: How to Cycle a Reef Tank |
Can You Skip Cycling a Reef Tank?

Phase 6 Verification

• ☐ Bottled bacteria product dosed on Day 1
• ☐ Raw shrimp added to tank on Day 1
• ☐ Ammonia tested every 2–3 days, results logged
• ☐ Nitrite tested every 2–3 days, results logged
• ☐ Ammonia confirmed at 0 ppm on two consecutive tests
• ☐ Nitrite confirmed at 0 ppm on two consecutive tests
• ☐ Nitrate detectable
• ☐ Shrimp removed from tank
• ☐ 30–50% water change completed
• ☐ Ammonia and nitrite re-confirmed at 0 ppm 24 hours after water change
• ☐ Post-water-change nitrate under 20 ppm

Phase 7, Add the First Livestock

The cycle is complete. The tank is ready for its first inhabitants. Move
slowly. Every addition is a biological event that the tank needs time to absorb.

Clean-Up Crew First (Week 1 Post-Cycle)

• Hermit crabs and snails consume detritus, algae, and uneaten food. They add minimal bioload and help establish a cleaner tank environment before fish are introduced.
• Starting count: approximately 1 snail per gallon, 1 hermit crab per 2–3 gallons for a beginner tank. Adjust down for a lightly fed, lightly stocked system.
• Acclimate using the drip method, float the bag for 15 minutes to equalize temperature, then drip tank water into the bag over 30–45 minutes before releasing.
• Do not add the bag water to the tank.
• Test ammonia 24 hours after adding the CUC to confirm biological filtration is handling the new bioload.

First Fish (2–4 Weeks After CUC)

• Choose a hardy, peaceful beginner species, an Ocellaris Clownfish pair is the standard first fish for good reason.
• Add no more than one or two fish for the first addition.
• Drip acclimate over 30–60 minutes before introduction.
• Test ammonia 24 hours and 48 hours after adding fish. Both should read 0 ppm. A spike indicates the biological filtration isn’t keeping pace, do a 20% water change and retest.
• Observe fish for 72 hours: eating behavior, gill movement, fin condition, white spots, behavior toward tankmates.
• Wait 2–4 weeks before adding the next fish.

First Coral (8–12 Weeks After Cycle Completes)

• Don’t rush this. The tank needs time to mature and parameters need to be stable for several consecutive weeks before corals are added.
• Before adding the first coral, run 4 consecutive weekly parameter tests and confirm: alkalinity stable at 8–10 dKH, nitrate under 10 ppm, phosphate under 0.05 ppm.
• First coral should be a mushroom coral or zoanthid frag, the most forgiving species available.
• Drip acclimate over 30–45 minutes. Place at lower light for the first 1–2 weeks and move up gradually.
• Observe for 72 hours before evaluating placement.
• Wait 2–3 weeks before adding the next coral.

See: Best Fish for a Beginner Reef Tank |
Best Beginner Corals for Reef Tanks

Phase 7 Verification

• ☐ Clean-up crew added first, drip acclimated, bag water discarded
• ☐ Ammonia confirmed at 0 ppm 24 hours after CUC addition
• ☐ Waited 2–4 weeks before adding first fish
• ☐ First fish drip acclimated, bag water discarded
• ☐ Ammonia tested at 24 and 48 hours after fish addition, both 0 ppm
• ☐ First fish observed for 72 hours, eating, normal behavior, no disease signs
• ☐ 2–4 weeks between each fish addition
• ☐ 4 consecutive stable weekly parameter tests before first coral
• ☐ First coral is a mushroom or zoanthid, drip acclimated
• ☐ First coral placed at lower light, not moved for minimum two weeks

Ongoing, The Maintenance Routine Starts Now

Setup is complete. The routine that keeps the tank healthy is what comes next, and it runs for the life of the tank.

Ongoing Setup Verification

• ☐ Log is active, every test result and addition recorded
• ☐ Weekly maintenance day chosen and scheduled
• ☐ RODI water supply maintained, adequate volume for weekly top-offs and bi-weekly water changes
• ☐ Alkalinity, nitrate, and salinity being tested weekly
• ☐ 10–15% water change scheduled every two weeks
• ☐ Filter floss being changed every 5–7 days
• ☐ Skimmer cup being checked and emptied weekly

See: Reef Tank Maintenance Guide