Tanks4theMemories
Community Member
- Joined
- Apr 3, 2026
- Messages
- 76
- Reaction score
- 133
- Location
- Philadelphia
- What state or country do you live in
- Pennsylvania
Hello, world 
I'm in the process of planning and setting up a ~40 gallon peninsula reef tank and thought it might be fun and useful to the community to document the process given the irregular build. I live in a rowhome in Philadelphia and this will be in my office on the second floor, so the main limiting factor for my tank options is weight. I would love to have a UNS R120, and would have bought one, but it's just too heavy. I've had a 25 gallon Waterbox peninsula AIO system set up for two years that this will be replacing, and I've learned a lot with that tank. Before that I was out of the hobby for about 12 years. Back in 2011–2013 I had a few different reef tanks with my dad, but those are all long gone. We had a 75 gallon, a 40 gallon, and a 210 gallon.
After doing some math, I've surmised that 40 gallons is about the max I'd feel comfortable with for the display. I really wanted something that gives me four feet of length to give a tang enough horizontal swimming space, and after some searching I found the Tideline 38.7 gallon tank (see it here on the supplier's website).
The tank dimensions are 47.3" x 13.8" x 13.8", which is about perfect within my constraints. I purchased a stand in walnut too, which should go well in my office. That all gets in next week, so I'll update the thread once I have it here.
For filtration, I want to get back to a sump instead of having another AIO. I didn't want to go above 10 gallons for the sump for weight, wanted a refugium chamber, and needed it to fit a Reefmat 250. Not finding anything that fit the bill, I bought a kit off eBay for a 10 gallon Aqueon tank and am going to build my own (kit below for reference).
Because the 10 gallon tank is only 10.5 inches wide, most refugium lights won't work or would look very clunky. The best option seems to be the UNS Mini refugium light screwed into an acrylic lid (like shown below).
The next issue is the lid itself. Since this is all custom, I'll have to source it. In searching for the best overflow box, I found Modular Marine and am having them build me a custom overflow box using their 800 GPH option to fit the back of the tank. I asked if they could do a custom lid for the sump as well, and that seems doable. Below is the diagram I sent over, so we'll see how it turns out.
And here are some rough test fits of everything to make sure my lid spacing was correct:
For sand, I currently have Caribsea special grade in the Waterbox 25, but it's just too coarse for my liking. I want something that reminds of home (Florida), and am going to try 40lbs of Bahama Oolite. I had it before years ago and recall it does tend to blow around, but I'll make it work. For rock, I went with one 20lb box of Caribsea LifeRock shapes and a 10lb box of LifeRock original. I figure that will give me some options to play with for the aquascape.
I also got a 15W Aqua UV sterilizer, a Maxspect Jump Gyre GF308 for flow (I have an MP10wQD on the Waterbox and have never found the app functionality to be worth anything--I set it once and adjust it using the buttons), a Syncra Silent 2.0 for the return pump, and a few other small items.
For lighting, I'm going to continue using my Kessil a360xe that I have on the Waterbox, but will either (1) sell it eventually and get three 47" Quanta Helix lights (two white and one blue), or (2) add a second Kessil a360xe for full coverage. Given the shallow tank depth, the Kessils feel like total overkill so I'm open to suggestions.
I think that covers most of the plan for now. As things come in and the build progresses, I'll continue to update the thread. Excited to see where this goes.
Best,
Alex
I'm in the process of planning and setting up a ~40 gallon peninsula reef tank and thought it might be fun and useful to the community to document the process given the irregular build. I live in a rowhome in Philadelphia and this will be in my office on the second floor, so the main limiting factor for my tank options is weight. I would love to have a UNS R120, and would have bought one, but it's just too heavy. I've had a 25 gallon Waterbox peninsula AIO system set up for two years that this will be replacing, and I've learned a lot with that tank. Before that I was out of the hobby for about 12 years. Back in 2011–2013 I had a few different reef tanks with my dad, but those are all long gone. We had a 75 gallon, a 40 gallon, and a 210 gallon.
After doing some math, I've surmised that 40 gallons is about the max I'd feel comfortable with for the display. I really wanted something that gives me four feet of length to give a tang enough horizontal swimming space, and after some searching I found the Tideline 38.7 gallon tank (see it here on the supplier's website).
The tank dimensions are 47.3" x 13.8" x 13.8", which is about perfect within my constraints. I purchased a stand in walnut too, which should go well in my office. That all gets in next week, so I'll update the thread once I have it here.
For filtration, I want to get back to a sump instead of having another AIO. I didn't want to go above 10 gallons for the sump for weight, wanted a refugium chamber, and needed it to fit a Reefmat 250. Not finding anything that fit the bill, I bought a kit off eBay for a 10 gallon Aqueon tank and am going to build my own (kit below for reference).
Because the 10 gallon tank is only 10.5 inches wide, most refugium lights won't work or would look very clunky. The best option seems to be the UNS Mini refugium light screwed into an acrylic lid (like shown below).
The next issue is the lid itself. Since this is all custom, I'll have to source it. In searching for the best overflow box, I found Modular Marine and am having them build me a custom overflow box using their 800 GPH option to fit the back of the tank. I asked if they could do a custom lid for the sump as well, and that seems doable. Below is the diagram I sent over, so we'll see how it turns out.
And here are some rough test fits of everything to make sure my lid spacing was correct:
For sand, I currently have Caribsea special grade in the Waterbox 25, but it's just too coarse for my liking. I want something that reminds of home (Florida), and am going to try 40lbs of Bahama Oolite. I had it before years ago and recall it does tend to blow around, but I'll make it work. For rock, I went with one 20lb box of Caribsea LifeRock shapes and a 10lb box of LifeRock original. I figure that will give me some options to play with for the aquascape.
I also got a 15W Aqua UV sterilizer, a Maxspect Jump Gyre GF308 for flow (I have an MP10wQD on the Waterbox and have never found the app functionality to be worth anything--I set it once and adjust it using the buttons), a Syncra Silent 2.0 for the return pump, and a few other small items.
For lighting, I'm going to continue using my Kessil a360xe that I have on the Waterbox, but will either (1) sell it eventually and get three 47" Quanta Helix lights (two white and one blue), or (2) add a second Kessil a360xe for full coverage. Given the shallow tank depth, the Kessils feel like total overkill so I'm open to suggestions.
I think that covers most of the plan for now. As things come in and the build progresses, I'll continue to update the thread. Excited to see where this goes.
Best,
Alex
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