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This thread is for the general discussion of the Article Member Spotlight: Dave Anderson (5,000-Gallon Concrete Reef).
Hello everyone! Today, we wanted to spotlight one of our members, @dca22anderson, and his incredible 5,000-GALLON TANK! Dave has put a lot of work into his tank, which you will learn about below, and I believe it reflects what we embody here at Reef2Reef. Sharing real stories from real reefers to help build a sense of real community. If you want to learn more about this tank, and follow more of @dca22anderson's incredible progress, be sure to check out his build thread HERE
To start, can you tell us a little about yourself?
My name is Dave Anderson, and I live in Utah. I’m lucky to have a wonderful, patient wife, Heather, who loves to ski—a hobby that conveniently allows for plenty of "fish time". We have four amazing children and live by the "Six F’s": Faith, Family, Food, Fish, Football, and Friends.
How did you get into the hobby?
My grandfather, who taught at a university in Southern California, kept small tanks in his study. Visiting him in Long Beach every Sunday as a child sparked my love for the mystery and possibilities of the aquarium. By age ten, I was hauling seawater from Huntington Beach Harbor for a 10-gallon tank on my dresser. I spent my weekends on my BMX bike visiting local fish stores, dreaming of the day I could afford something larger.
What do you love most about the hobby?
I love the creative freedom—specifically the challenge of taking raw materials like acrylic, concrete, rebar, epoxy, and sand and forming them into a naturalistic habitat. There is immense satisfaction in watching a DIY build come together step-by-step; the only limits are your imagination and the family budget.
A 5,000-gallon tank is incredibly impressive. What made you want to build a tank this size?
Growing up in the shadow of SeaWorld San Diego and MarineLand of the Pacific, I was inspired by their massive concrete exhibits. I loved seeing fish demonstrate natural behaviors in spaces where they seemed unfazed by their environment. As a teenager, I set a goal to build a giant concrete aquarium to provide the most realistic home possible for my reef fish.
As you can imagine, this seems like a dream setup for many of us. Do you still feel that way about it?
Absolutely. While a bigger tank brings bigger problems, it also brings bigger rewards. I still love this tank and everything it represents. I genuinely enjoy the constant challenge of improving the filtration, water quality, and system.
What was your design process like for a system this large?
Information on concrete aquariums was scarce, so I researched concrete block koi ponds with viewing panels in the UK and worked closely with a mentor who had built a 20,000-gallon reef. I hand-drew the plans for the tank and filtration, making copies to use as a guide for every measurement until it was perfect. If you want to see those original sketches and the stages of the build, I’ve documented the journey on my R2R Build Thread.
How is planning a tank this size different from planning the average home aquarium? In what ways is it still similar?
With a tank this size, what kinds of structural or engineering considerations did you have to account for to make it safe and reliable and to avoid leaks?
I overbuilt everything. I took my mentor's recommendation of 12”- on-center rebar and doubled it to 6”- on-center. The walls and acrylic windows are thicker than required. The foundation is a 12” concrete floor with extra reinforcement. My advice for DIYers: do your research, check your work twice, and if you can afford it, consult a professional.
What was the actual build process like?
It was a joyful journey that involved my entire inner circle. My sons helped dig the 12’x12’ hole in our basement floor, and my daughter helped silicone the viewing panels. My wife, brother, and "fish buddies" all pitched in to lift acrylic viewing panels and stage rockwork. The highlight was finally removing the forms to expose the concrete walls, filling the tank with saltwater, and releasing the first fish into their new home.
Do you have any funny or memorable stories from the build?
We almost lost the back wall during the concrete pour when a support brace broke, leaving a slight bulge in the center of the back wall. To keep neighbors from asking about the piles of dirt coming out of the basement, my wife had me build garden boxes so we could "hide" the evidence. Also, my daughter’s TikTok of her "disappearing" into the 3-foot deep hole in our floor was a classic.
What kind of equipment are you running on a tank this size? Would you be willing to share an equipment list?
I run heavy-duty gear from MRC, PantaRhei, Neptune Apex, Deltec, and Sicce. I use Ecoxotic commercial cannons for lighting, supplemented by numerous Reefbrite XHO strips.
How do you make sure the tank gets enough light and flow?
I use the gyre method to keep water tumbling across the bottom, up the front glass, and into the overflows. This is driven by a Panta Rhei ECM75, five Sicce 4000s, and four 1-1/2” Sea Swirls.
Have there been any lighting or flow challenges on a tank this size that surprised you or that the average hobbyist might not think about?
The sheer cost of backup equipment is a hurdle. A backup main internal circulation pump can cost $7,000–$10,000. I once had a controller fail and had to ship it to Germany for repair; during that month-long wait, I lost 85% of my corals because the flow demand was simply too high for smaller backup pumps to handle.
What does your daily maintenance routine look like? Weekly? Monthly? Yearly?
Are you doing water changes, and if so, what does that process look like on a system this large?
I do monthly water changes via an inline system. I use a 300-gallon barrel that I can isolate, drain with a sump pump, refill with RODI, add salt, mix, and then bring back online to infuse the new seawater.
How do you handle dosing? What are you dosing, and how much of it is automated versus manual?
I have automated dosers for Lanthanum and Kalk. I manually dose Lugols on a weekly basis.
How do you decide what kinds of livestock to keep in your tank?
The tank has seen different "eras." It started with massive Unicorn and Vlamingii tangs, but they were like bulls in a china shop with my SPS. Now, I’m enjoying large Angelfish. I love that a tank this size allows the hobbyist to morph and change focus over time.
How do you manage livestock compatibility in such a large system?
I still follow the classic rule: easy-going fish first, aggressive fish last. Even with 5,000 gallons, established residents will still work to maintain dominance over newcomers.
How do you handle cleaning the tank? How much is done by your clean-up crew versus manual cleaning?
I use a Mighty Magnet once a week on the acrylic panels. Because my wrasses tend to eat the clean-up crew, most of the cleaning is manual, though I have plenty of urchins to help "take the algae edge off".
If pests get introduced, how do you identify, track, and deal with them in a tank this size?
Prevention is key, but I also rely on "go-to" fish like wrasses, copperband butterflies, and cleaner shrimp to keep things in check naturally. When meds are necessary, it takes a lot of them.
Who or what in the hobby has influenced or inspired you the most?
The "Mr. 4000" thread on Reef Central and Andrew Sandler's builds (Polo Reef) were huge inspirations. I also looked at monster fish keepers and koi hobbyists—I figured if their methods worked for them, they’d be even better for a reef.
What have been the biggest challenges, and how did you work through them?
The biggest biological challenge is an infestation of green palythoas that encrust over my nicer corals. Economically, the rising costs of power, water, and salt are a major factor making it harder to save for retirement!
What has been most rewarding about building and owning an aquarium of this size?
Watching my four kids give guided tours to their friends is incredibly rewarding. We’ve hosted everything from youth groups to math class outings. Seeing the amazement on people's faces reminds me how special this hobby is.
Do you have any regrets about taking on a tank of this size, or any words of caution for someone considering it?
No regrets at all. However, you must have the time and money to keep it all up; if you lack either, you'll wish you'd built a pool instead. Design it for ease of maintenance and automate whatever you can.
What do your family and friends think about the tank?
We love it. It’s the perfect backdrop for meaningful conversations with our kids and friends. Now that our friends are having grandkids, they bring them over for "aquarium tours" too.
Is there anything you wish people understood about owning a reef tank of this scale?
While it’s more stable, it takes a lot of work to keep it "dialed in." An ICP test can lead to several hundred dollars in dosing just to catch up on elements. Also, tracking livestock is hard—sometimes a fish will disappear for weeks due to aggression, only to sometimes reappear later in its full glory.
What’s one bit of reefkeeping wisdom you would like to share with the community?
If you see something, fix it now. Whether it’s a coral getting stung, a pump making a weird sound, or a doser running low—don't wait.
What will you do differently on your next tank build?
I won't go quite as deep. I’ll also move all equipment into a giant concrete sump attached to the back wall of the tank, add more room above the tank, and definitely install extra 20-amp breakers.
Any final thoughts you’d like to share?
I want to give a massive shout-out to the Reef2Reef community. There were days during this build—especially when digging that massive hole in my basement or dealing with broken braces—where I was ready to throw in the towel and just build a swimming pool. The encouragement, advice, and sheer enthusiasm from the members here kept me moving forward. This hobby can be isolating when you're working on a DIY project of this scale, but R2R makes it a shared journey. If you want to see this beast in action, come hang out with me on my build thread here on R2R. Happy reefing!
To start, can you tell us a little about yourself?
My name is Dave Anderson, and I live in Utah. I’m lucky to have a wonderful, patient wife, Heather, who loves to ski—a hobby that conveniently allows for plenty of "fish time". We have four amazing children and live by the "Six F’s": Faith, Family, Food, Fish, Football, and Friends.
How did you get into the hobby?
My grandfather, who taught at a university in Southern California, kept small tanks in his study. Visiting him in Long Beach every Sunday as a child sparked my love for the mystery and possibilities of the aquarium. By age ten, I was hauling seawater from Huntington Beach Harbor for a 10-gallon tank on my dresser. I spent my weekends on my BMX bike visiting local fish stores, dreaming of the day I could afford something larger.
What do you love most about the hobby?
I love the creative freedom—specifically the challenge of taking raw materials like acrylic, concrete, rebar, epoxy, and sand and forming them into a naturalistic habitat. There is immense satisfaction in watching a DIY build come together step-by-step; the only limits are your imagination and the family budget.
A 5,000-gallon tank is incredibly impressive. What made you want to build a tank this size?
Growing up in the shadow of SeaWorld San Diego and MarineLand of the Pacific, I was inspired by their massive concrete exhibits. I loved seeing fish demonstrate natural behaviors in spaces where they seemed unfazed by their environment. As a teenager, I set a goal to build a giant concrete aquarium to provide the most realistic home possible for my reef fish.
As you can imagine, this seems like a dream setup for many of us. Do you still feel that way about it?
Absolutely. While a bigger tank brings bigger problems, it also brings bigger rewards. I still love this tank and everything it represents. I genuinely enjoy the constant challenge of improving the filtration, water quality, and system.
What was your design process like for a system this large?
Information on concrete aquariums was scarce, so I researched concrete block koi ponds with viewing panels in the UK and worked closely with a mentor who had built a 20,000-gallon reef. I hand-drew the plans for the tank and filtration, making copies to use as a guide for every measurement until it was perfect. If you want to see those original sketches and the stages of the build, I’ve documented the journey on my R2R Build Thread.
How is planning a tank this size different from planning the average home aquarium? In what ways is it still similar?
- Differences: Everything is upscaled—space, materials, cost, and maintenance. You can no longer do water changes with buckets. Maintenance delays can turn into weeks of corrective work, and you have to manage a mountain of gear, from 21 light fixtures to 12 pumps.
- Similarities: The core principles—water parameters, flow, and lighting requirements—remain the same. You still deal with livestock aggression and tank/gear leaks, and even in 5,000 gallons, Zebrasoma tangs will still fight for dominance.
With a tank this size, what kinds of structural or engineering considerations did you have to account for to make it safe and reliable and to avoid leaks?
I overbuilt everything. I took my mentor's recommendation of 12”- on-center rebar and doubled it to 6”- on-center. The walls and acrylic windows are thicker than required. The foundation is a 12” concrete floor with extra reinforcement. My advice for DIYers: do your research, check your work twice, and if you can afford it, consult a professional.
What was the actual build process like?
It was a joyful journey that involved my entire inner circle. My sons helped dig the 12’x12’ hole in our basement floor, and my daughter helped silicone the viewing panels. My wife, brother, and "fish buddies" all pitched in to lift acrylic viewing panels and stage rockwork. The highlight was finally removing the forms to expose the concrete walls, filling the tank with saltwater, and releasing the first fish into their new home.
Do you have any funny or memorable stories from the build?
We almost lost the back wall during the concrete pour when a support brace broke, leaving a slight bulge in the center of the back wall. To keep neighbors from asking about the piles of dirt coming out of the basement, my wife had me build garden boxes so we could "hide" the evidence. Also, my daughter’s TikTok of her "disappearing" into the 3-foot deep hole in our floor was a classic.
What kind of equipment are you running on a tank this size? Would you be willing to share an equipment list?
I run heavy-duty gear from MRC, PantaRhei, Neptune Apex, Deltec, and Sicce. I use Ecoxotic commercial cannons for lighting, supplemented by numerous Reefbrite XHO strips.
How do you make sure the tank gets enough light and flow?
I use the gyre method to keep water tumbling across the bottom, up the front glass, and into the overflows. This is driven by a Panta Rhei ECM75, five Sicce 4000s, and four 1-1/2” Sea Swirls.
Have there been any lighting or flow challenges on a tank this size that surprised you or that the average hobbyist might not think about?
The sheer cost of backup equipment is a hurdle. A backup main internal circulation pump can cost $7,000–$10,000. I once had a controller fail and had to ship it to Germany for repair; during that month-long wait, I lost 85% of my corals because the flow demand was simply too high for smaller backup pumps to handle.
What does your daily maintenance routine look like? Weekly? Monthly? Yearly?
- Daily: Visual inspection of gear, checking sump levels, and ensuring no water is on the floor.
- Weekly: Top off dosers (Lanthanum, Kalk, etc.), wipe viewing panels, and check reactors, manually dose Lugols.
- Monthly: Replace Carbon and GFO, deep-clean the skimmer, and check flow and lighting.
- Yearly: Change UV bulbs/sleeves, swap out RODI filters, clean out media reactors.
Are you doing water changes, and if so, what does that process look like on a system this large?
I do monthly water changes via an inline system. I use a 300-gallon barrel that I can isolate, drain with a sump pump, refill with RODI, add salt, mix, and then bring back online to infuse the new seawater.
How do you handle dosing? What are you dosing, and how much of it is automated versus manual?
I have automated dosers for Lanthanum and Kalk. I manually dose Lugols on a weekly basis.
How do you decide what kinds of livestock to keep in your tank?
The tank has seen different "eras." It started with massive Unicorn and Vlamingii tangs, but they were like bulls in a china shop with my SPS. Now, I’m enjoying large Angelfish. I love that a tank this size allows the hobbyist to morph and change focus over time.
How do you manage livestock compatibility in such a large system?
I still follow the classic rule: easy-going fish first, aggressive fish last. Even with 5,000 gallons, established residents will still work to maintain dominance over newcomers.
How do you handle cleaning the tank? How much is done by your clean-up crew versus manual cleaning?
I use a Mighty Magnet once a week on the acrylic panels. Because my wrasses tend to eat the clean-up crew, most of the cleaning is manual, though I have plenty of urchins to help "take the algae edge off".
If pests get introduced, how do you identify, track, and deal with them in a tank this size?
Prevention is key, but I also rely on "go-to" fish like wrasses, copperband butterflies, and cleaner shrimp to keep things in check naturally. When meds are necessary, it takes a lot of them.
Who or what in the hobby has influenced or inspired you the most?
The "Mr. 4000" thread on Reef Central and Andrew Sandler's builds (Polo Reef) were huge inspirations. I also looked at monster fish keepers and koi hobbyists—I figured if their methods worked for them, they’d be even better for a reef.
What have been the biggest challenges, and how did you work through them?
The biggest biological challenge is an infestation of green palythoas that encrust over my nicer corals. Economically, the rising costs of power, water, and salt are a major factor making it harder to save for retirement!
What has been most rewarding about building and owning an aquarium of this size?
Watching my four kids give guided tours to their friends is incredibly rewarding. We’ve hosted everything from youth groups to math class outings. Seeing the amazement on people's faces reminds me how special this hobby is.
Do you have any regrets about taking on a tank of this size, or any words of caution for someone considering it?
No regrets at all. However, you must have the time and money to keep it all up; if you lack either, you'll wish you'd built a pool instead. Design it for ease of maintenance and automate whatever you can.
What do your family and friends think about the tank?
We love it. It’s the perfect backdrop for meaningful conversations with our kids and friends. Now that our friends are having grandkids, they bring them over for "aquarium tours" too.
Is there anything you wish people understood about owning a reef tank of this scale?
While it’s more stable, it takes a lot of work to keep it "dialed in." An ICP test can lead to several hundred dollars in dosing just to catch up on elements. Also, tracking livestock is hard—sometimes a fish will disappear for weeks due to aggression, only to sometimes reappear later in its full glory.
What’s one bit of reefkeeping wisdom you would like to share with the community?
If you see something, fix it now. Whether it’s a coral getting stung, a pump making a weird sound, or a doser running low—don't wait.
What will you do differently on your next tank build?
I won't go quite as deep. I’ll also move all equipment into a giant concrete sump attached to the back wall of the tank, add more room above the tank, and definitely install extra 20-amp breakers.
Any final thoughts you’d like to share?
I want to give a massive shout-out to the Reef2Reef community. There were days during this build—especially when digging that massive hole in my basement or dealing with broken braces—where I was ready to throw in the towel and just build a swimming pool. The encouragement, advice, and sheer enthusiasm from the members here kept me moving forward. This hobby can be isolating when you're working on a DIY project of this scale, but R2R makes it a shared journey. If you want to see this beast in action, come hang out with me on my build thread here on R2R. Happy reefing!
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