Broadcast Feeding SPS Colonies Technique Guide

SPS corals feed on particles most reefers never bother measuring, and the difference between skeletal growth and pastel coloration often traces back to a broadcast routine rather than any flashy supplement. A correct broadcast feeding sps colonies technique delivers micronised zooplankton and bacterioplankton across every polyp in the tank, not at one head with a pipette. This guide from Gensou Aquascaping at 5 Everton Park walks through the particle sizes, pump cycles and Singapore water realities that make broadcast feeding work in practice, not just in theory.

Why SPS Need Broadcast Rather Than Target

SPS polyps are tiny, typically 1 to 3 mm across with a mouth opening under 300 microns. Pipette feeding a Stylophora or Montipora colony is mechanically absurd because each colony carries hundreds of mouths. Instead, SPS capture suspended food from the water column during brief windows when flow is gentle enough for polyp extension but fast enough to deliver particles. Broadcast feeding exploits those windows deliberately.

Choosing the Right Particle Size

SPS corals accept particles from 5 microns (bacterioplankton) up to around 250 microns (small rotifers and oyster egg fragments). Products such as Reef Chili, Polyp Lab Reef Roids and finely ground Coral Frenzy sit in this range. Frozen mysis is too large and wastes ninety per cent. Our coral pellet foods deep dive covers the particle sizing across common brands.

Pump Reduction, Not Total Shutdown

Unlike LPS feeding where you kill all pumps, SPS broadcast feeding benefits from residual flow. Cut powerheads to 20 to 30 per cent, leave the return running at half speed, and food circulates past every colony rather than settling on the substrate. A five to seven minute reduced-flow window strikes the balance between delivery time and polyp extension. Pump controllers with a feed mode manage this automatically; the reef automation guide covers programming.

Mixing the Broadcast Slurry

Dry powder dropped straight into the tank clumps on the surface film and feeds the skimmer cup rather than the corals. Always pre-mix in a 100 ml cup of tank water, shake until uniform, and pour gently into a high-flow return path. A quarter scoop of Reef Chili in a 400 litre tank twice weekly is a starting dose; scale up only if polyps extend visibly for more than an hour and nutrients stay stable.

Timing Within the Lighting Cycle

SPS polyps extend most during the transition periods at dawn and dusk. Broadcast feeding immediately before lights ramp up, or during the final ramp-down hour, captures those extended windows. Feeding mid-photoperiod when polyps are retracted wastes the entire dose. A LED dimmer schedule that includes long ramps gives you predictable extension windows.

Bacterioplankton as a Complement

Live bacterioplankton products such as Fauna Marin Bacto Reef Balance or AquaForest Bio S feed the SPS mucous layer and resident symbionts more than the polyp itself, but the coloration effect is measurable over eight weeks. Dose these separately from coral foods, usually late evening once the skimmer has been off for fifteen minutes. Skim pause before dosing prevents an expensive plume from ending up in the cup.

Nutrient Monitoring Around Feeds

Broadcast feeding adds measurable phosphate and nitrogen over a week. Track nitrate weekly with a low-range test kit, aiming for 2 to 8 ppm in lean SPS tanks, and phosphate with a Hanna ULR meter between 0.02 and 0.05 ppm. If either metric climbs, cut feed frequency rather than increasing export; the SPS coloration chemistry guide explains why the nutrient ratio matters more than the absolute number.

Skimmer Management During Feeds

Turn the skimmer off for fifteen to thirty minutes after each broadcast dose so the food circulates rather than skims out. Set a phone timer or use an Apex FeedA cycle to restart it automatically. Running the skimmer through a feeding session wastes most of the food and overflows the cup within an hour.

Adjusting for Singapore Water Temperature

Tropical ambient temperatures push SPS tanks toward the upper tolerance band for many species, especially Acropora tenuis and A. millepora. Feed in the morning before the afternoon heat peak, when dissolved oxygen is highest and metabolism is sustainable. Chillers running hard during afternoon feeds reduce polyp extension as flow and temperature fluctuate. Our reef tank Singapore start guide covers chiller sizing for HDB conditions.

Signs SPS Are Actually Being Fed

Visible signs of successful broadcast feeding include prolonged polyp extension, thickening at colony bases, faster growth measured against fixed reference points such as frag plugs, and more vibrant coloration in the outer growing tips. If you see none of these after six weeks of consistent feeding, the problem is usually flow distribution, light intensity, or baseline nutrient levels rather than food type.

Common Mistakes to Avoid

Dosing too much too quickly, feeding while the skimmer runs, using particles too large, feeding only when polyps are retracted and mixing too many products into one dose all defeat the routine. Keep the protocol boring: one product, one volume, one time slot, tracked weekly. When something changes, change only one variable and observe for two weeks before tweaking again.

Related Reading

• SPS Coral Coloration Chemistry Guide
• Coral Pellet Foods Deep Dive
• How to Feed Corals Target Feeding Reef
• Acropora Coral Care Guide SPS
• Montipora Coral Care Guide SPS