REEF OF THE MONTH - April 2021: Jack Ravensbergen's Awesome Cube Reef!

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R2R Username: @Jack Ravensbergen
Build Thread:
Jack's Tank


Hi everyone! I am very honored that my tank is featured as the Reef of the Month. There are so many tanks that look great as well, so this means a lot to me.

I am Jack. I'm 57 yrs old, and I live with my better half and two kids in Katwijk aan Zee in Holland (europe). Katwijk lies about 15 miles from Amsterdam and is more known that's why my location on my account is Amsterdam.

Besides reefing, my other hobbies are diving, cooking, motorcycling and (coming this summer) kayaking.

Here's my backyard...

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Here's my front yard...

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Here's me and my treasures...

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I lived my whole life next to the Northsea and was always interested in the life in it. After my time in the Army, I had my first saltwater tank in 1985. I bought it from a good friend of mine. This friend is Willem Zwanenburg and from him i learned the first steps in our fantastic hobby. This is my fifth tank now and this one is mostly sps dominated and is close to 185 gallons.

System Profile:
  • Display tank dimensions: 105 cm x 80 cm x 80 cm
  • Stand: 90 cm high, custom built by Mark at Coral & Frags in Wassenaar Holland (the woodwork I made myself).
  • Sump: 25g
  • Protein skimmer: Bubble King 250
  • Carbon/phosphate filtration: Vertex with phosphate remover from Triton (al99) & Aqua Medic ozone 100
  • Return pump: Red dragon 12,000 liters
  • Water circulation: Maxspect 280xf vertical mounted and partly the return pump
  • Lighting (display): 2 philips coral care gen2 180 watts each running at max 80%
  • Calcium/alkalinity/magnesium dosing equipment: 2 Kamoer pumps
  • Auto top-off: Tunze 3155
  • Heating: 600w titanium heater
  • Cooling: Bleu Marine 800
Here's a photo of the tank when it was first getting started:

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And here it is today!

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Water Circulation and Flow Summary and Objectives:

I run 2 Maxspect 280 at 40%. They are opposite each other in order to create a strong flow of nearly 12,000 gallons/hour.

Water Parameters:
  • Temp: 78/80 F
  • pH: 8.2/8.4
  • Salinity: 34/35 ppm
  • NO3: 5
  • Ca: 420/430 ppm
  • Alk: 8.5/8.8 dkh
  • Mg: 1400 ppm
  • PO4: 0.06
  • Ammonia and nitrites: 0
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What salt mix do you use?

I use Reef Crystals. I've never had any problems with it, so why change something that's good. :)

What kind of rock did you start with?

30 kilos live indonesian rock & 15 kilos dead rock. I made the scape using cement.

Calcium/Alkalinity/Magnesium Summary and Objectives:

I like to keep Alkalinity, calcium, and magnesium higher than natural seawater. Po4/No3 are somewhat higher than normal. That's why alk is kept higher as well

What and how do you dose for the big 3 (alk/cal/mag)?

Until February 2020, I always had a calcium reactor (Dastaco), but I heard very good things around me about ATI Pro Essentials. This is a two bottle system which has all the main and trace elements that you need for your reef, and works very good for me. I now dose these using 2 Kamoer pumps.

I check the main 5 once or twice a week (ca/alk/mg/po4/no3). Every 3 months I send over a ATI ICP test to the lab, and with those results i can adjust the trace elements.

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What is your maintenance routine?
Feed the fish, clean the glass, check ro water, skimmer, temp, and enjoy the tank. :)
Weekly: Test the big five, clean the skimmer and back wall.
Monthly: Clean the sandbed, water change 10% ( sometimes every two weeks).

Tank Inhabitants—Fish: (Please List)
  1. 2 yellow tangs (5 years)
  2. 1 tomini tang (5 years)
  3. 5 chromis (2 years)
  4. 1 betta (21 years)
  5. 1 copperband (3 years)
  6. 2 psychedelic mandarin
  7. 2 pictichromis
  8. 2 kauderni cardinals
  9. 2 ocellaris clowns
  10. 1 diamond wrasse
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Other Invertebrates:
  1. Tridacna clam from red sea
  2. 5 sand sifting sea stars
Tank Inhabitants— Corals: (Option to List)
  1. Stylophora purple
  2. Montipora digitata red / grey / green
  3. Montipora hirsuata
  4. Montipora superman
  5. Montipora rainbow
  6. Montipora gold rush
  7. Montipora capitata
  8. Montipora appleberry
  9. Montipora capricornis red
  10. Montipora capricornis green
  11. Anacropora green goblin
  12. Anacropora green slimeball
  13. Acropora hyacinthus
  14. Acropora strawberry
  15. Acropora frogskin
  16. Acropora echinata
  17. Acropora digitifera
  18. Acropora aspera
  19. Acropora formosa bleu
  20. Hystrix
  21. Caliendrum bleu/green
  22. Pocillopora bleu
  23. Pocillopora yellow/green
  24. favia green
  25. Pavona maldivensis lime
  26. Turbinaria reniformis
  27. Acanthastrea
  28. Blastomussa
  29. Clavularia
  30. Euphyllia ancora
  31. Euphyllia torch toxic green
  32. Gorgonia purple grey
  33. Mushroom blue
  34. Mushroom superman
  35. 20 varieties of zoas
and I'm probably forgetting something... :)
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Fish and Coral Feeding:

Once a day my tank gets copecoden, mysis, lobster eggs, sushi leaves.

Any stocking regrets?

The blue tang: When I bought him, he was as small as a postage stamp, but in 3 years he's well over 7"!
Some zoas like the alien explosions... Their name says it all.

Any fish, invert, or coral you will NEVER keep?

I would never keep special gorgonians, dendranthema, or angel fish.

What do you love most about the hobby?

There's always something new every day and the challenge to make it work. I also love that help is always around the corner if you need it with fellow reefers.

How long have you been doing this?

I started in 1985, so this year is 36 years.

Who was responsible for getting you into the hobby?

Willem Zwanenburg who is my good friend that sold me my first tank and taught me the hobby.

Who or what in the hobby most influences/inspires you?

Nature itself. I like to have my own slice of reef as natural as possible. I try to show this in my scape and placement of coral.

Favorite fish?

The betta. This fish lived for 15 years in Wim's tank and now for 6 years in mine.


Favorite coral?

My favorite coral is Montipora. It's easy to keep, has nice colours, and it's not so sensitive like most acroporas.

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How do you typically get over setbacks?

Ups and downs are normal in this hobby. Don't be a cry baby. Get over it and learn of your mistakes.

What are your future plans for improvement/upgrade of the tank?

No new plans at this time...

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Any special tips for success or advice you'd like to share with other reefers?

Nothing in this hobby goes fast (except dollars :) ). Take your time with everything and read a lot before you buy.

Final Thoughts?

Special thanks goes to Mark and bas of Coral & Frags Wassenaar Holland. These two guys helped me when the previous tank blew in 2016. that's a long story....

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How healthy are your fish?

  • All of them are Healthy

    Votes: 312 80.8%
  • Most of them are Healthy

    Votes: 50 13.0%
  • Half of them are Healthy

    Votes: 3 0.8%
  • Most are Unhealthy

    Votes: 4 1.0%
  • All are Unhealthy

    Votes: 5 1.3%
  • Other (please explain)

    Votes: 12 3.1%

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