Reef Frag Rack Setup Guide: Magnetic and Acrylic Options
A well-placed frag rack is the difference between frags that thrive and frags that languish on the sand bed. This reef frag rack setup guide from Gensou Aquascaping at 5 Everton Park walks through magnetic versus acrylic designs, sizing for nano reefs common in Singapore flats, and the acclimation routine that takes a new frag from shop bag to display rockwork in six weeks without a single burnt tip. Most HDB reefers skip the rack entirely and learn the hard way when a $80 acro browns out on sand.
Why a Dedicated Rack
Frags need controlled light, flow and easy access for inspection. Direct placement onto rockwork locks in a decision before you know how the coral responds. A rack lets you quarantine-observe for 14 days, gradually shift positions upward over four weeks, and pull any frag that shows RTN without disturbing the scape.
Magnetic Racks
Magnetic racks attach to the inside glass via a two-part magnet, holding frag plugs on acrylic shelves outside the primary rockscape. Strong neodymium pairs hold through 10 mm glass reliably; avoid the cheap Carousell versions that slip under Singapore water temperatures.
Upside: easy repositioning, no rock footprint, excellent light exposure against the glass. Downside: visible front-facing, algae hotspot, glass scratches if the magnet is dragged.
Acrylic Rockwork Racks
Frag plugs slotted into a drilled acrylic board laid flat on an elevated ledge. Better for larger tanks where a dedicated mid-level zone exists. The Innovative Marine and Mr Saltwater branded boards cost around $25 to $45 locally; DIY versions from laser-cut acrylic run under $10 if you have access to Sim Lim Tower cutting services.
Placement: Light Tier
Start frags at 100 to 150 PAR regardless of the adult target. A rack positioned at the tank’s mid-height sits in that range under most Singapore-installed AI Hydras and Radions. Measure with a borrowed Apogee MQ-510 or ask a local reef club for a loan; guessing PAR by eye fails consistently.
Ramp upward by 30 PAR every week until reaching the target display position.
Placement: Flow Zone
Moderate laminar flow over the rack, not turbulent. Aim for frag-scale flow where polyps extend but do not whip violently. A single gyre pump directed across the rack works; two opposing powerheads create turbulence that shreds polyp tissue on new frags. See gyre pump versus powerhead flow for matching pumps to tank geometry.
Dipping Before Racking
Every new frag gets dipped in Bayer or Coral RX for 10 minutes, then freshwater rinsed, then placed on the rack. Skipping dip introduces flatworms, nudibranchs, red bugs and montipora-eating sundials. Quarantine tanks are ideal but a dipped rack in the display is the realistic floor.
Sizing for Nano Tanks
For AIO nanos under 100 litres, a 4-plug magnetic rack is the practical limit. More frags than that dominates the scape visually and creates flow dead zones. If you routinely bring in new coral, dedicate a 20 to 40 litre frag tank plumbed off the display rather than overloading.
Labelling and Tracking
Each plug gets a numbered drop of UV-cure reef putty or a waterproof marker on the underside. Maintain a spreadsheet recording source, price, date, dip result and acclimation status. Scaling this habit turns into a useful inventory when insurance claims or trades arise.
Acclimation Timeline
Week 1: racked at lowest light tier, minimal direct flow, observe twice daily for RTN or pest activity. Week 2: shift to target flow zone, raise light by 30 PAR. Week 3: raise another 30 PAR if polyp extension remains strong. Week 4: final PAR target reached; evaluate placement candidate on rockwork. Weeks 5 to 6: transfer to permanent spot using reef-safe putty.
Fragging Racks for Propagation
A secondary low-light rack is useful for grow-out of freshly fragged mother colonies. Place in a shaded overhang or lower water column where 80 to 120 PAR keeps growth steady without stressing fresh wounds. Iodine dosing at trace levels post-frag accelerates healing.
Maintenance and Cleaning
Racks accumulate cyano and hair algae within a month in warm Singapore tanks. Remove the rack weekly, scrub the open slots with an old toothbrush, rinse in tank water, and replace. Never dry-scrub; the biofilm you disturb is partly protective coralline recruitment.
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