75 gal DIY Mixed Reef Build

[willy00]

Hey everyone, welcome to my 75 gal DIY mixed reef build thread! I wanted to document the process of building this tank from research, planning, saving money, all the way to stocking. This will be my first 'real' reef tank as I upgrade from a 15-gallon LPS-focused AIO tank to a proper system with a sump and a variety of livestock. Many things attract me to reef keeping, but I think most of all, it is my curiosity to learn and succeed in a challenging hobby. This build is truly DIY and involves carpentry, electrical, metal fabrication, a custom sump build, 3D printing, and this is before water even goes in the tank. I hope this thread can be useful for others planning similar projects, as well as a fun way to meet other hobbyists and share tips and tricks along the way!

 

[willy00]

My vision for this tank is to build a mixed reef with utilitarian fish, using methods to keep maintenance minimal, and to focus on enjoying the tank. This is an expensive hobby, no two ways about it, but I hope to find a balance of spending money wisely and DIYing where appropriate.

The barrier to entry for me when I developed an itch for reef-keeping a few years ago was the immense cost of the tank itself, along with getting my wife on board with the idea. We compromised on starting with a 15 gal AIO tank from reef casa, which was a much more manageable entry point than the several thousand dollar systems popular these days. I have had this tank running for 3 years and learned some valuable lessons preparing for a larger system. Patience, water changes, and an accurate salinity tester was all I really needed to succeed with this tank, but it was so easy to get sidetracked with the amount of information available.

This brings the thread back to the starting point, the tank itself. My dad had the same idea of upgrading about 15 years ago from a 20 to 75 gal and had actually purchased a 75 gal reef ready aqueon tank. This tank sat empty in his basement for a while, and he ended up giving it to me. Although the tank was never filled, exposed to UV, or temperature changes, I wanted to do a thorough leak test before proceeding with anything else. The first test was 24 hours, then I emptied the tank completely and did another 7 days with no leaks! I painted the back of the tank black with krylon fusion spray paint which worked pretty well. This helped me clear the initial price hurdle and saved at least $700 had I pursued the exact same tank new, but honestly, I would've continued to save for an innovative marine tank for an indefinite amount of time if this tank wasn't an option.

 

[willy00]

After leak testing was complete, I started the electrical work to add a dedicated 20 amp circuit for the tank. Most of the work was fishing wire through I-beams and around HVAC in the basement to get to my mechanical room behind where the tank sits. While I was at it, I also added dedicated 20 amp circuits for a future electric fireplace and 2 wet bar outlets on the adjacent wall to the tank. This took a long time, mostly because I wanted to tear out as little drywall as possible. I used 12/2 romex wire for the dedicated 20 amp circuits and installed GFCI outlets. Once I got to the breaker box in the garage, my father-in-law, an electrical engineer, helped safely install 3 arc fault breakers for the new circuits. This was the only part of the process I opted to not 'Do it myself' due to the amount of current coming into the panel and needing proper installation. I did get a permit and inspection from the regional building department for peace of mind. I passed the inspection, and the total cost for materials and permits for this was around $400. I got 2 quotes from electricians to do this which ranged from $800-$1500 without repairing any drywall, hence the DIY decision.

 

[willy00]

The next step was the stand. Recruiting family help is the continuing theme here. I could've made a simple plywood or 2x4 stand, but I wanted it to be sturdy, professional looking, and resistant to water damage. Conveniently, a hobby of my dad's is welding. He welded a custom galvanized 1 inch steel tube frame for the base of the stand and I built a plywood frame to surround it as a cabinet. To make the metal frame rust resistant, it was primed and painted with topside marine paint.

I was initially planning on marine grade plywood, but after chatting with the employees at the lumber supply store, I decided to go with Baltic birch. For those that are curious, marine grade plywood is best used for applications that are constantly exposed to moisture such as trailer beds. Baltic birch is highly water-resistant wood because each layer of ply is filled and glued to eliminate gaps for moisture to enter. Since the plywood was painted and coated multiple times with oil based urethane, it will be highly resistant to moisture. The stand has 5 doors with soft close, inset hinges that I covered in vaseline to limit rust, along with all of the nuts/bolts used to mount the plywood to the metal. I wanted to make sure I had access to every part of the sump, and could remove it if necessary.

The pictures show the process of constructing face frames, doors, and the top/bottom of the stand. I cut a rectangle in the top plywood to allow passage of the drains from the overflow and maintenance access. The right side of the stand is being used for a DIY board for power strips and controllers. There was one 'oops' moment where the control board was too close to the control door, and I had to use a hole saw to drill room for the door hinge to be. Cutting, sanding, gluing, painting, and coating the stand took several weekends and the cost of the stand was about $350, because the metal was already on-hand from a past project.

 

[willy00]

Equipment:
20 gal long DIY sump with glass baffles
Reef Octo 110 sss skimmer
Reef Octo Varios 4 return pump
2x Eheim jager tru temp 150w heaters with inkbird 306t controller
BRS single dosing pump
BRS carbon/GFO reactor with sicce syncra 1.5 pump
2x Kessil A360xe lights with kessil mounting arms
Tunze eco chic refugium light
Red Sea ATO with external 20 gal resevoir
2x jebao/jecod sow8 wavemakers (not yet installed)
American DJ power strip
Kasa wifi powerstrip

 

[Gumbies R Us]

Following along!

 

[willy00]

Sump:

The sump is designed to use a refugium as the primary nutrient exporter, growing macroalgae and pods, while also not having to use filter socks. I used a 20 gal long and had a glass shop cut glass baffles to create 3 primary compartments. I got the 20 gal long on a great sale at petsmart for $16 and the glass baffles cost about $70. I used GE silicone 1 and made quite a mess of adhering the baffles to the tank. It looks pretty ugly, but the water flows exactly as intended. I tried using tape, wood blocks, and bricks, but the over/under/over section proved difficult to keep clean. I got it all siliconed, but its far from professional. It's a sump after all...

The first section has an eggcrate basket holding pond matrix which I will be replacing with a filter media cup because the flow of the primary drain blasts pond pebbles everywhere lol. The skimmer and carbon reactor are also in the first compartment. The second compartment has the emergency drain, heaters, and will be the refugium once Chaeto becomes available again. There is filter floss sitting on a 3D print/pvc bracket after the refugium to capture anything not supposed to go back into the display, and the baffles seem to be eliminating bubbles as intended. The final compartment has the return pump and ATO sensor. I have not decided how to mount the Varios float switch in the return chamber or if I'm going to use it at all. I installed some pond liner stapled to the plywood frame inside the cabinet to catch any accidental spills, as well as a pond liner curtain to limit salt creep behind the tank.

This is my first attempt using a refugium to export nutrients so I will report back on how this is going once it's running. The skimmer is off but I will probably turn it on once adding more fish/feeding to the system. I will be dosing all for reef into the sump once the demand for ca/mg/alk increases. Long term my plan is to use AFR, macroalgae, and carbon/GFO to maintain stability, with larger water changes as needed, ideally once per quarter.

 

[Subarody]

Looking forward to seeing what’s next with your build! I’m in the process of building a stand for a 75G…but it’s going to be a slow build before I actually get water in the tank. Enough time for me to see what you’re doing:)

 

[willy00]

Looking forward to seeing what’s next with your build! I’m in the process of building a stand for a 75G…but it’s going to be a slow build before I actually get water in the tank. Enough time for me to see what you’re doing:)

More updates coming!

 

[willy00]

Plumbing

The reef-ready Aqueon tank is designed to use a single durso pipe and a return line inside the overflow. The bulkhead holes are drilled 1" and 3/4" in this tank. I wanted to have an emergency drain so I opted to use both of the pre-drilled holes to make a herbie overflow, with the primary, full-siphon drain being the 3/4 inch. I used one gate valve on the primary drain and this allows for fine tuning of the water height in the overflow. The emergency drain is set up to trickle when the ATO tops off in the sump. I followed the herbie overflow setup on the gmac reef website and it is virtually silent.

The return line is plumbed behind and over the top of the tank. All of the PVC in this build is standard white schedule 40 aside from the 2 90 deg elbows for the top of the return line for aesthetic purposes. I did a rough calculation and tested the backflow volume the sump can handle, with about 1 inch of room to spare. I highly recommend testing the backflow volume of the sump to sleep soundly at night. The last piece worth mentioning is that I added multiple unions throughout the plumbing for easy disassembly or maintenance, since everything is hard plumbed. Leak test passed, on to the next!

 

[willy00]

Aquascape

This is probably my favorite part of the build process because working with rocks to make something unique and appealing to the eye is really fun! Scaping in the 75 gal footprint is quite challenging because there's not a lot of depth to work with. My goal for the mixed reef is to have one side for mostly LPS and the other to try a few SPS with a bonsai type look. I also wanted to balance habitat/hiding for my stocking list without filling the whole tank with rock. I used a combo of mined dry rock and marco rock, and a thin, instant set CA superglue to build a few structures. The best binding substrate for the CA glue was marco rock crushed up into a powder, but this takes forever. Unless you love hitting rocks with a hammer for hours, a good alternative is crushing dry aragonite with a mortar and pestle.

I will be adding my existing rock from my 15 gallon to fill in the back left corner. I think I will go through several versions of the scape but this is the starting point:

 

[willy00]

I added 40 lbs of carib sea special grade sand mixed with 40 lbs of fiji pink to add some habitat for wrasses and jawfish. This creates about a 2 inch sand bed in a 75 gallon. I added the carib sea water clarifying packets which cleared the water up in about 24 hours. After adding water and sand, I realized that half of my initial aquascape was buried. I removed the rock, dried it and added some more height to the bottom of the main 2 structures by gluing the same way with thinset superglue and crushed aragonite. As a side note, taking some larger pieces of dry rock and filing them on the concrete outside worked perfectly for flattening the base of the main structures instead of buying the very expensive foundation rocks. I thought the picture of the main tank lights on with the tunze refugium light looked really cool before the water cleared up so here's that: