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Cris Capp's 500-Gallon Reef

Cris Capp's 500-Gallon Reef

by Cris Capp
Volume
500 gal
Dimensions
8ft x 36" x 36"
Tank type
SPS Dominant
Runs a calcium reactor alongside a Kalkwasser/Nilsen reactor so the calcium reactor's pH-lowering effect is offset by the Kalk reactor's pH-raising effect, letting him dose more Kalk for its added benefits (raising pH, adding calcium/alkalinity, precipitating phosphate).

Cris Capp's roughly 9-year-old, 500-gallon (8ft x 36 x 36) SPS-dominant reef sits in his AquaticArt support facility in Denver, recently rebuilt into a Planet Aquariums glass tank after a suspect seam on the old acrylic. It runs bare-bottom with heavy flow (two MP60s, two MP40s, ~1500 gph return), 400W radium halides supplemented by AI Hydra 52 blues, and a Berlin system anchored by paired calcium and Kalkwasser reactors. It houses standout colonies including a massive Jedi Mind Trick Montipora, the Hurlock Gani Goniopora, and Space Invader Pectinia that he fragments heavily every few months.

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Source: YouTube · Reef Builders
What sets this tank apart
Paired calcium + Kalk reactors
Runs a calcium reactor alongside a Kalkwasser/Nilsen reactor so the calcium reactor's pH-lowering effect is offset by the Kalk reactor's pH-raising effect, letting him dose more Kalk for its added benefits (raising pH, adding calcium/alkalinity, precipitating phosphate).
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Aggressive scheduled fragging
Rather than let signature colonies overtake the tank, he hacks 30-40% off fast growers every 4-5 months and distributes the big chunks into his service accounts, keeping the display balanced while stocking clients.
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Halide base + Hydra blue supplement
Keeps 400W radium metal halides as the foundation for his SPS and layers four AI Hydra 52 units running blues-only to add color, a deliberate hybrid instead of an all-LED or all-halide setup.
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Equipment Breakdown

Shop this build · 1 of 6 items priced
Cris Capp's 500-Gallon Reef — Full Equipment List
$837
est. build cost
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Lighting
Radium 400W metal halide bulbs
Radium
400W metal halide bulbs
Display lights ×4
Four 400W Radiums — 1,600 watts on an 8-hour photoperiod; he ran AI Sol LEDs for a while and switched back to halides.
Modern equivalent: EcoTech Radion XR30 G6 →
Aqua Illumination Hydra 52
Aqua Illumination
Hydra 52
Blue supplementation ×4
Blues run at full blast purely to offset the white-heavy halide look — LEDs as actinic supplement, not primary light.
Modern equivalent: AI Hydra 64 HD →
Flow & Circulation
Dolphin Aquasea Ampmaster 6250
Dolphin
Aquasea Ampmaster 6250
Return pump
Pressure-rated external pushing ~1,500 gph of real turnover into the 8-foot display.
Modern equivalent: Abyzz A-Series Return Pump →
EcoTech Marine MP60
EcoTech Marine
MP60
Wavemakers ×2
⭐ Premium pick
Big guns of a four-VorTech array on this bare-bottom 8-footer — flow was raised steadily over the years and the torches and Goniopora thrive on it.
$836.99 Buy → at Bulk Reef Supply Details →
EcoTech Marine MP40
EcoTech Marine
MP40
Wavemakers ×2
Backs up the MP60 pair with mid-level flow — four VorTechs total keep detritus suspended over the bare bottom.
In our catalog →
Dosing
GEO Calcium reactor + Kalk (Nilsen) reactor
GEO
Calcium reactor + Kalk (Nilsen) reactor
Ca/Alk supplementation
The CO2 reactor's pH drag is cancelled by the Kalk reactor's pH lift, letting him dose more kalkwasser for its bonus effects — pH, Ca/alk, phosphate precipitation.
In our catalog →

Husbandry & Notes

  • Berlin-style filtration: two large skimmers plus media reactor running carbon or GFO as needed.
  • Runs both calcium reactor and Kalk (Nilsen) reactor together so pH shifts offset each other.
  • Bare-bottom tank; increased flow steadily, which torches and Goniopora thrive on.
  • Fragments fast-growing colonies every 4-5 months, removing 30-40% to keep tank in check.
  • Broadcast feeds Brightwell phyto (Reef-O + Reef-S mix) 2-3x weekly; doses Acro Power amino acids.
  • ~1500 gallons/hour real turnover via pressure-rated return pump feeding the display.
  • Water chemistry first: master temp, pH, salinity, calcium, magnesium, alkalinity before enhancements.
It has to start with water chemistry, first and foremost.
You can have ten thousand dollars worth of lights and your dKH is six-five, it's not gonna work.
If I hadn't fragged it, it would be at least half the tank and probably up until the glass.
If you want colorful corals, keep healthy corals and everything else will fall in line.
I'm such a big proponent of using a calcium reactor with a Kalk reactor.