The Gear List for an SPS Coral Reef Tank in Australia: A Real Build

Six months ago the tank was full of Kenya trees and toadstools that grew if you looked at them wrong. Now there's a frag of Walt Disney sitting under the light and it's already going brown at the base. This is the point every softie keeper hits eventually. The gear that ran a mixed reef tank for two years suddenly isn't enough, and the coral is telling you about it in real time.

SPS corals are not more delicate than softies, they're just less forgiving of drift. Softies shrug off a swing in alkalinity or a dead spot in flow. Acropora, Montipora and Pocillopora show stress within days. The fix isn't more gear for the sake of it, it's the right four systems working together: light strong enough to drive growth, flow that reaches every branch, dosing that holds calcium and alkalinity steady, and a way to watch it all without staring at the tank every hour of the day.

The build

This is roughly what a 300 to 450 litre SPS conversion looks like once the softies have been rehomed and the rock has been scrubbed back to bare skeleton.

• Lighting: A pair of Kessil LED fixtures or an AI Hydra series light, run at 400 to 500 PAR at the sand bed tapering to 250 to 300 at the tips, depending on species and depth. This is the single biggest lever for colour and polyp extension in Acropora. Undersized lighting is the most common reason SPS frags brown out and never recover.
• Flow: Two wavemakers positioned on opposite corners, angled to cross in the middle of the tank rather than blast straight at the glass. Random or pulse mode beats a single steady stream. SPS branches want turbulent, multidirectional flow that reaches the underside of the frag rack, not just the top of the display.
• Dosing: A calcium and alkalinity dosing setup from our unidose range, set to hold alkalinity between 7 and 8 dKH and calcium around 420 to 440 ppm. Manual dosing works early on, but growth rate and daily consumption climb fast once the colonies establish, and that's when a doser earns its keep.
• Testing: Salifert test kits for calcium, alkalinity and magnesium, checked two to three times a week while dialling in the doser, then weekly once stable.
• Monitoring: An Apex controller with a pH and temperature probe, set to alert by email or app if either drifts outside range. This is what catches a stuck pump or a heater failure at 2am before it becomes a dead tank.
• Frag prep: CoralRx One Shot for dipping new frags before they go anywhere near the display, and a stack of ceramic frag tiles for mounting cuttings as the colonies grow and need splitting.

Before and after

Before: a single strip light rated for softies, one return pump doing all the flow work, alkalinity tested when someone remembers, no alarms if anything goes wrong overnight. The tank looks fine because soft corals tolerate that setup indefinitely.

After: PAR meter readings logged monthly, two wavemakers running alternating patterns, a doser topping up calcium and alkalinity daily in small doses instead of one big weekly dump, and an Apex quietly watching pH and temp in the background. The Acropora that was browning out under the old light starts pushing new growth tips within three to four weeks under the upgraded PAR, and it holds colour instead of fading to brown the moment lighting intensity drops or nutrients spike.

What actually moves the needle first

If the budget has to be staged, lighting and flow come first because they affect coral health daily. Dosing consistency comes second, since stable parameters matter more than perfect parameters. Monitoring comes last in terms of urgency but pays for itself the first time it catches a failure while you're at work or asleep.

Common questions on the switch

Do I need to replace my whole light to keep SPS?
If your current fixture can't push 300+ PAR at the top of the rockscape, yes. Most single-strip LEDs built for softies and LPS won't get there even on max intensity.

How many wavemakers does a 400 litre SPS tank need?
Two is the practical minimum for even coverage. One placed to hit the display directly and one for cross flow behind the rockwork gives branching corals flow from more than one direction.

Can I dose calcium and alkalinity by hand instead of using a doser?
Early on, yes. Once you're adding SPS colonies regularly and consumption climbs, manual dosing gets harder to keep consistent, and consistency is what SPS actually needs.

Prices mentioned in this article are accurate at the time of publishing and are subject to change. Please check the product page for the current price before purchasing.