Getting Started with SPS Corals: What Every Beginner Should Know

Making the Jump to SPS

Comfortable with softies and LPS? SPS corals — small polyp stonies — are the next challenge. These are the corals that build reef structures in the wild, and they demand stable, clean water to thrive. The jump to SPS is rewarding, but the learning curve is real.

The holy trinity to nail:

Alkalinity (dKH): 8–9.5 dKH. The exact number matters less than consistency. A swing of more than 0.5 dKH per day causes problems fast
Calcium: 420–440 ppm. Their skeleton is calcium carbonate, so they pull this constantly
Magnesium: 1280–1350 ppm. Keeps the alk/cal relationship in check

A Hanna checker for alk is essential, and quarterly ICP tests are worth every penny once SPS are in the tank. Knowledge is cheaper than dead corals.

Where to Actually Start

Not all SPS are created equal. Some are genuinely beginner-friendly; others punish the slightest instability.

Good starting species:

Montipora capricornis — the plating monti. Grows quickly, tolerates more than most SPS, and gives that "SPS keeper" buzz early on
Montipora digitata — branching monti in purple or green. Hardy for an SPS
Stylophora — chunky, colourful, more forgiving than any acropora. A perfect stepping stone

Then graduate to:

Acropora millepora — the classic beginner acro. Still fussy, but reasonable
Acropora tenuis — slim branches, gorgeous colours, moderately demanding

It pays to keep simpler species alive for six months minimum before moving to designer acros.

Flow and Light

SPS need proper flow — not a washing machine, but enough that nothing settles on the tissue. Aim for 20–50x tank turnover per hour with some randomness from a wavemaker.

Lighting-wise, most reefers run 200–400 PAR at the coral. But start low with new frags — place them near the bottom and move up gradually over 2–3 weeks to avoid light shock. Light shock is real and it's ugly.

Buying First SPS

Wild-caught acropora shipped from overseas can arrive with parasites and days of shipping stress. For a first SPS purchase, aquacultured frags from UK hobbyists are a much safer bet — already adapted to captive conditions with shorter shipping times. Browse SPS corals from UK sellers and filter by aquacultured. Check seller feedback and ask how long they've had the piece.

Patience Is Key

New SPS will often brown out initially — a normal stress response where excess zooxanthellae mask the fluorescent pigments. Recolouring happens over weeks as the coral acclimates. The key is keeping parameters rock solid and resisting the urge to move things around. When that first acro starts throwing growth tips, nothing beats it.

What species did everyone start with for SPS? Any beginner-friendly recommendations beyond the usual suspects?