The Ark

merickson45 · Feb 6, 2021

I'm starting up a coral spawning experiment tank and I decided to keep a tank journal to help monitor progress. Since I don't have tons of space, I went with an RSR 170 bought from @dandemeyere (thanks again!). The tank has been cycling a few months and is in the post cycle ugly phase right now. Fish and snails only at the moment, corals are in QT (converted old tank) until it is ready. The tank is controlled by a reef-pi and can simulate seasonal solar, lunar and temperature variations. I've got two main goals for this tank:

Stock the tank with two of each type of coral, let them sync up to the seasonal variations, and see I can get them to spawn.
Fertilize the eggs from step 1 and grow out some baby corals.

Successful spawning would already be cool, but succeeding at growing out baby corals would be amazing. I realize this is very ambitious and there will be many naysayers, but I've done a decent amount of research already and I'm optimistic. Worst case scenario I end up with a nice display tank! More details below for those interested.

Equipment:
Tank: RSR 170 with modified sump (refugium divider)
Solar lights: Kessil A360 (x2)
Lunar lights: small 4000K LEDs (x2)
Heater: 200W Titanium Heater with BRS Ink Bird controller
Chiller: None currently, will buy if needed
Skimmer: Axium X-120
Return pump: Sicce 2.0
Powerheads: IM Wavelink Midsize (x2)
Aquascape: MarcoRocks dryrock and CaribSea dry aragonite sand

Fish:
Clownfish (x1)
Royal Gramma (x1)
Pajama Cardinalfish (x2)
Court Jester Goby (x1)
Yellow Watchman Goby (x1)

Inverts:
Tiger Sand Conch (x1)
Assorted Trochus, Astrea and Cerith snails

Tank with post-cycle uglies

Sump with reef-pi (top right)

Old tank converted to coral QT

Nitty gritty details:
In order to simulate the seasonal patterns necessary to get corals to spawn, I built a reef-pi controller and set it up to control:

solar lighting (two Kessil A360s)
lunar lighting (two small 4000K LEDs attenuated to provide low light levels)
temperature (BRS WiFi Ink Bird controller)

Using reef-pi and a few custom python scripts, I programmed the solar, lunar and temperature changes to follow the seasonal changes of an Australian reef. Seasonal temperature and solar data were obtained from J. Craggs' 2017 paper and lunar data is calculated using the python Skyfield package. The Kessil lights are controlled using 0-10V cables, the lunar lights are controlled using a 0-12V output, and the Ink Bird is controlled over WiFi using the tinytuya Python package. The solar/lunar intensity, sunrise/sunset times, moonrise/moonset times and temperature are automatically updated daily. The reef-pi also has four peristaltic pumps for dosing, a water level sensor and a temperature probe.

Here goes nothing!

Coral reefer · Feb 6, 2021

Looking forward to your experiment. Good luck!

Squist · Feb 6, 2021

Following along! Good luck!

merickson45 · Apr 21, 2021

Decided it was time for a quick update. First corals are in! They've actually been in for almost a month, I just haven't had time to update. All have been doing well, even the Acro frag I added as a water quality "canary" seems quite happy. I'll probably move the leathers back to my qt later on, just didn't have space there at the moment. So excluding those, the current list is:

Montipora digitata - orange/green
Montipora digitata - blue
Micromussa Lordhowensis - red/blue
Micromussa Lordhowensis - blue
Micromussa Lordhowensis - white/green/black
Acanthastrea echinata - orange/green
Euphyllia Paradivisa - green/purple
Duncanopsammia axifuga - blue/green
Caulastrea spp. - neon green (species unknown)
Goniopora spp. - pink (species unknown)
Acropora spp. - pink/green (species unknown)

If anyone thinks they can help identify the unknowns, I'd be very grateful. I'll post close-ups of them further down.

The tank is still going through some uglies, but looked worse just a few weeks ago. I'm hopeful that things will stabilize even more in the next month. Been adjusting feeding and filtration to try and find the right balance. I also started triton dosing a few weeks ago which seems to have helped. Overall just trying to make slow, minimal corrections to guide things in the right direction.

I'm currently planning to build a simple canopy with zipper curtains to block out ambient light when the tank solar lights are off (since that's known to be important for coral spawning). I'll post more pictures when that is done. That's all for now!

Close-ups of unknown species:

svreef · Apr 21, 2021

Cool!

merickson45 · Jan 8, 2023

Been a while, new baby and a big move took priority. But the tank survived both my neglect and the move, although there were a couple corals lost. There were some pretty significant changes along the way, including a rescape for better flow and grow out space. I also had to re-home a bully clownfish last year.

The tank went through pretty much every ugly possible, but it finally stabilized around 6 months ago and corals are finally growing rather than just surviving. Right now, the tank is home to:

1 Pajama Cardinalfish
1 Coral Beauty Angelfish
1 Tailspot Blenny
1 Yellow Watchman Goby
1 Randall's Pistol Shrimp
1 Tiger Sand Conch

I'll revise the coral list soon. I'm hoping to post updates more regularly going forward. Happy reefing!