How to Set Up a Coral Frag Grow-Out Tank: Layout for Propagation
Growing out coral frags is where the hobby crosses into genuine husbandry — and a dedicated propagation setup accelerates growth dramatically compared to fragging in your display tank. This coral frag grow out tank aquascape guide walks you through layout, equipment, and techniques that produce healthy, saleable frags in the shortest time. At Gensou Aquascaping Singapore, our propagation systems have produced thousands of frags over two decades, and the principles are surprisingly straightforward.
Choosing the Right Tank
Shallow, wide tanks outperform tall ones for frag grow-out. A depth of 20-30 cm provides uniform light distribution across the entire frag rack, eliminating the shading and PAR drop-off that deeper tanks create. A 90 x 45 x 25 cm tank is an excellent starting point, offering ample rack space without consuming too much floor area — an important consideration in compact Singapore homes. Low-iron glass is not necessary here; standard float glass works perfectly since aesthetics are secondary to function.
Frag Rack Layout
Egg-crate (light diffuser grid) remains the most cost-effective and versatile racking material. Cut panels to fit your tank dimensions and elevate them on PVC pipe legs roughly 5-10 cm above the substrate. This elevation allows detritus to settle below the frags rather than accumulating on them. Position racks in a single layer for uniform light exposure. Magnetic frag racks from brands like InvisiFrag offer a cleaner look and easier repositioning, though they cost more — around $30-60 per rack on Shopee.
Organise frags by species or light requirements. Group SPS frags under the brightest zone directly below your fixture, and place softies and LPS toward the periphery where light is slightly lower. Label rows with waterproof tags to track growth rates and lineage.
Lighting for Fast Growth
Consistent, moderate-to-high light drives the fastest encrustation and branch extension. A PAR range of 150-250 across the rack surface suits most SPS and LPS frags. T5 fluorescent fixtures remain popular for grow-out tanks due to their even light spread, though LED panels work equally well. Run a photoperiod of 10-12 hours with a gradual ramp-up and ramp-down to simulate natural conditions. Avoid the temptation to blast frags with maximum intensity — stressed corals brown out rather than grow.
Flow and Circulation
Strong, turbulent flow accelerates coral growth by delivering nutrients and removing waste from tissue surfaces. Position a wavemaker at each end of the tank, set to alternating or pulse mode, creating random turbulence across the frag rack. Flow should be strong enough to keep frag plugs clear of settling detritus but not so powerful that it dislodges freshly glued frags. Aim for 20-40 times total tank volume in turnover per hour.
Filtration and Water Quality
A simple sump with a protein skimmer handles biological and mechanical filtration efficiently. Run activated carbon to remove organic compounds and terpenes released by soft corals. Maintain alkalinity at 8-9 dKH, calcium at 420-450 ppm, and magnesium at 1,300-1,400 ppm for optimal SPS growth. Automated dosing systems pay for themselves quickly in a grow-out setup by maintaining rock-steady parameters without daily manual dosing. Singapore’s soft PUB tap water needs remineralisation when preparing saltwater — use a quality salt mix and RO/DI water.
Feeding and Supplements
Target-feed frags twice weekly with amino acids, phytoplankton, or coral-specific foods like Reef-Roids. Broadcast feeding also works in grow-out tanks, as the dense frag population captures food efficiently. Amino acid supplements demonstrably improve colouration and growth rates in SPS corals — dose according to manufacturer recommendations and observe the response over several weeks before adjusting.
Harvesting and Trading Frags
Most frags are ready for sale or trade once they have fully encrusted their plug and begun extending new growth — typically four to eight weeks for fast growers like Montipora and Stylophora, longer for slower species. Singapore’s active reef community on Carousell and hobbyist forums provides a ready market. Document growth with dated photographs to build credibility as a frag seller. Well-grown, fully encrusted frags command better prices and return customers.
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emilynakatani
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