By Bob Goemans
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Dave Botwin's Aquarium

Note to Viewers: After speaking to the Los Angeles Marine Aquarium Society in late 2003, I had an opportunity to visit with this aquarist and view his systems later in the evening. Unfortunately, it was very late at night, about midnight, and it was raining as we stood outside his home looking at the various stony frags in his 'outside' propagation tanks. Even under those conditions and with the system lit only with an overhead light, which you can see in one of the attached photos, it was quite impressive. They contained some very rare Acropora species! And since Dave sells these extremely hardy and naturally raised frags, I suggest visiting his website at for more info about his systems and available corals.

Bob Goemans


Owners Name: Dave Botwin

Location: Encino, CA, USA

Year the tank was set up: May 1989

Size and Volume of the Tank: Display Tank - 60"L x 18"W x 24"D 125 gallon acrylic tank with overflow and drilled with a closed loop overflow that feeds two outside Frag tanks, which are 76 gallons each. My Frag tanks and all sumps and filtration are located outside in direct sunlight in the back of my home. My Fish-Only system is nine years old and is gravity connected to a 30 gallon seahorse tank in another room. The display reef tank and 225 gallon fish-only tanks are located inside my home.

Sump Size: 100 gallon Truv - Modified with baffles and 22 gallon refugium, (2) 250 gallon. Tomato Tank Sumps, (1) 360 gallon water tank buried 6' in ground for GeoThermal cooling.

Refugium: Called a "propagation tray" - plastic sweater box 12" x 6" x 16"

Pounds of Live Rock: Almost 1000 pounds total (400 pounds of Tonga in reef system)

Sand Type/Depth: 2" in Display tank, 2" in Frag tanks, 2" in Tomato Tub Sumps

Type of Biological Filtration: Live Rock, Live Sand, Refugium and huge quantities of Chaetomorpha in 250 gallon sumps


Main system pumps: Dolphin Ampmaster 3000GPH - Split output, half to display tank half to frag tanks.

Additional pumps: RIO Powerheads for additional water movement, with 4 in the 125 reef tank

Reactors: Homemade 9 gallon Kalkwasser Reactor, Larry Hawk Dual stage Calcium reactor

Protein Skimmers: Euroreef GS 8-2

Monitoring Equipment: Milwaukee SMS 122 monitors pH of Calcium Reactor effluent, Milwaukee SMS 122 pH controller - connected to solenoid to bleed CO2 into system when pH gets too high, Milwaukee ORP Controller, Ranco Temperature Controller, and Pinpoint Marine Salinity Meter

Wavemakers: Hayward 2" Motorized Ball Valve for returns to display tank.

Doser: Old Hospital Monitors for Strontium and Magnesium

Chillers: 360 gallon tank buried in the ground, 1/2hp chiller - plumbed but not used (System is too big)

Refugium: Dedicated Refugium is 22 gallon, but I have added Chaetomorpha to my (2) 250 gallon sumps, I grow about 2 - 4 plastic grocery bags of it per week.

Denitrator: None

Trickle Filter: None

Unique Equipment: I flow water through a total of 8 tanks using only a single Dolphin Ampmaster. I use gravity to flow the water from tank to tank to tank. I also use the gravity from the overflow in the display tank to pump water to my 22 gallon refugium, 1/2hp chiller and Calcium Reactor.


Inside Lamps: 750W of 250W DE HQI Helios 20K bulbs in PFO Reflectors, 130W of VHO Actinic for tank wake up, CSL Moonlights - Cause they are cool!

Outside: Direct Sunlight

Photoperiod: 2 hrs of moonlight, 4 Hrs of Actinic, 9 hours of Halide, 2 Hrs of Actinic, 1.5hrs of Moonlight, 5 hours of Airstones after lights are off


Water Temperature:in the Winter - Low 80's in the summer - about 80 - 81ºF

Specific Gravity: 1.026

PH: 8.2 - 8.5

Calcium:450 - 500 ppm

Redox: 400+

Alkalinity: 12 - 14 dKH

Nitrate: zero

Nitrite: zero

Ozone: 500mg/hr - 24-7

Phosphate: Essentially 0 by LaMotte - But high Silicate levels from local water source

Additives: Kalkwasser, Calcium reactor, Magnesium, Strontium, Lugol's Iodine

Water Changes: 150 gallons every 3 to 4 weeks - But I evaporate out over 20 gallons a day- replaced automatically with Kalkwasser from RO.

RO/DI water: RO for Topoff, Kold-Steril for water changes

Brand of Salt Mix: Coralife


I feed the fish flake or frozen about 2 to 3 times a week. For the first 13 years of this tank I fed the fish maybe 6 times a year. The corals I occasionally (less than weekly) feed Golden Pearls, Phytoplankton, and Cyclopeeze.


Front glass cleaned about once a week, and dust and salt deposits removed from covers and lights. Partial water change, about five gallons, every month. Excess algae removed weekly. Corals trimmed as needed. Protein skimmer cup emptied and cleaned when it gets full. Siphon tubes for both the overflow and propagation tray are cleaned whenever they start collecting too many bubbles.


Please visit my website where more is explained and where you can directly contact me.

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