Nautical_Nathaniel's 40 Gallon Cube Temporary Expansion Project

nautical_nathaniel · Jun 16, 2026

So I've got myself in a pickle, but as far as pickles go it's not a bad pickle, just a problematic pickle...

Here's the pickle:

You see, I've run out of room in my Waterbox 20 AIO and my corals are getting too close to the glass. I can't scrape around them without hitting the purple stylo in the back or knocking a few tentacles off of the hammer. Flow is also not great right now. I also have way too many fish right now, mostly due to acquiring the next piece of this puzzle...

This is an old Innovative Marine 40 Cube that I found on Facebook marketplace and got for $300. By itself $300 doesn't seem like a good deal but it came with several corals, a few fish, various equipment, and a Radion XR15 Gen 4. So pretty decent deal for all of that.

I quickly found out that no modern media or pictures exist for this tank (if you know of some I'd appreciate the links/pics). Best I can figure out this is like a 2012-2015 model, maybe. It has 4 baskets that sit in the back center chamber that hold filter floss/media/etc. and that's about it.

I've started getting a few pieces of equipment to get it going, but I need to build a stand for it. It came with a stand but it's a bit too tall for my liking.

My plans are to build a new stand, get this up and running, take my entire aquascape from the 20, and plop it in the 40. This will serve as a temporary setup until I can get my dream 4 foot wide or bigger setup.

Anyways, I just wanted to get a build thread going in case anyone else comes across one of these "vintage" tanks and decides they want to get it running too. Even if it's temporary for my current corals and some of the fish, I might eventually turn it into a frag or anemone/mushroom growout tank. Either way I'll try to keep this build thread updated as I set it up and we'll see where it goes!

KrisReef · Jun 18, 2026

Looking around found this link, but I can’t tell you if the new baskets fit your tank?

https://topshelfaquatics.com/produc...KSIpowjio5HJw907knKzyHl-tKtwqfAcaAmlEEALw_wcB
This might work:
https://www.innovative-marine.com/s...dglZ9pqQpWEvyUq3XPAa-W6BIx4XUlucaAv8kEALw_wcB

nautical_nathaniel · Jun 18, 2026

KrisReef said:
Looking around found this link, but I can’t tell you if the new baskets fit your tank?

https://topshelfaquatics.com/produc...KSIpowjio5HJw907knKzyHl-tKtwqfAcaAmlEEALw_wcB
This might work:
https://www.innovative-marine.com/s...dglZ9pqQpWEvyUq3XPAa-W6BIx4XUlucaAv8kEALw_wcB

Yea unfortunately the newer baskets and accessories don't fit. Thanks for looking though!

The biggest problem stems from the height of the chambers. They span the entire height of the tank whereas most IM AIO tanks now have a standardized floor height in the filter and accessory chambers.

I'm gonna run the baskets with filter floss in the top one, carbon/other chemical media (if needed) in the second basket, and the Sera Sipprax porous media in the bottom two baskets. I'll reassess after a month or two to see if I need to come up with some other solution for the filter baskets.

nautical_nathaniel · Jun 29, 2026

Small update, been working on the stand and here's where it's at:

This has been my first time building any sort of cabinet. My last DIY stand was 2x4s with plywood nailed to the outside. I wanted this one to be a bit more functional.

I still need to cut out the equipment cord hole in the back and mount some shelves or a rack for the power strip. I'm also thinking about making some small aquarium tool holders to put on the door, just gotta see what I can make with the plywood scraps.

After I figure that stuff out, I'll disassemble what I can, sand, prep, stain, and clear coat the outside. I planned on priming and painting the inside with some leftover high grade paint from home renovations.

Justfebreezeit · Jun 29, 2026

Nice it looks real good. Interested to see where this goes.

nautical_nathaniel · Jul 7, 2026

I managed to get my stand finished and also built a light rack out of 1/2" conduit. So far I've been able to install the return pump and heater in the back of the tank, but that was mostly to see what kind of room I would have for a HOB skimmer.

I was hoping to have it up and running soon but I decided to rearrange my home office and that includes this new setup. I'm also waiting on an equipment order that includes the hanging kit for my Radion XR15, so it will continue to sit empty until those items have been resolved!

Justfebreezeit · Jul 7, 2026

Stand looks professional good job.

Good idea with the conduit. Good looking and cost effective. Have you used it before? Holds the weight no problems?

nautical_nathaniel · Jul 7, 2026

Justfebreezeit said:
Stand looks professional good job.

Good idea with the conduit. Good looking and cost effective. Have you used it before? Holds the weight no problems?

Thanks!

Yea one of my previous tanks had a similar light stand although I had it shaped like an upside down "U" with the legs going down the sides of the tank. They were constantly in the way for maintenance so I decided to have them go down the back on this one using the 90 degree connectors to make the overhang. Shouldn't be in the way as much this time around.

I feel like the weight of an XR15 and two reefbrite strips shouldn't be too much for it, but if it is I'll probably scrap it and find a wall mounted bracket. I'm trying to avoid tank mounted light racks for now since my current Waterbox 20 has a small chip in the back glass from my Radion tank mount.

nautical_nathaniel · Jul 9, 2026

It's got water in it!

Still waiting on the hanging kit for my light, it supposed to arrive next week at some point (my fault for ordering from a place with known issues).

In the meantime, I'm going to let it sit a couple days with RODI water running through it and then probably add my salt and sand to get a cycle started with a bit of bacteria starter. I'll call it a prolonged leak test or something

nautical_nathaniel · Jul 13, 2026

It's alive!!!

I've added saltwater, sand, Fritz 9 starter bacteria, and a Maroon Clownfish that was getting bullied in my other tank. I also set up the light hanging kit and one of my Radion XR15 Gen 4's, but I still plan on adding my Reefbrite strip lights and their mount to this tank so the lighting still needs some work.

In the stand I have a giant mess of cords and a 10 gallon Bashea ATO reservoir. The ATO I'm running is the XP Aqua Duetta 2. Eventually I will do some wire management once I have all of my equipment.

While testing the ATO I figured out the chamber with the return pump in it doesn't fluctuate much. The most water movement I saw was in the middle chamber which also holds my filter/media boxes. This wasn't exactly where I wanted the ATO sensor to go but I guess it will have to do for now.

In the meantime I will be making sure the tank is somewhat cycled. Since I'm adding very established rocks and corals, I'm not too worried about the tank having issues cycling but I'll be sure to keep a close eye on things the first few months.

I'm also still waiting on a skimmer to come in. I think I want the Aquaready Bullet 2.0 HOB skimmer, but it seems to be sold out everywhere. I currently have it backordered at two different places. I may end up cancelling both of those orders and just going with something else if I feel like I need something sooner. There's already a bit of brown foam in chamber 1 from the overflow, but I think that's mostly from the freshly added sand.

MushroomMan101 · Jul 13, 2026

I am a big fan of 40 cubes! Can’t wait to see the aquascape of this one.

Justfebreezeit · Jul 14, 2026

Nice. Looks like the light mount worked perfectly.

nautical_nathaniel · Jul 14, 2026

Justfebreezeit said:
Nice. Looks like the light mount worked perfectly.

Yes it did! Still think it's way overpriced for what you get but oh well

Gumbies R Us · Jul 14, 2026

Following along!

nautical_nathaniel · Jul 17, 2026

I've transferred my aquascape, coral, fish, and a few critters over to this tank. Look at all that extra space!

Current stock list:
Flame Angel
Starry Blenny
Blue Devil Damsel
Purple/Strawberry Dottyback
Flame Shrimp
A Few Mexican Red Leg Hermits

Gonna wait a few weeks before adding more cleanup crew. I will definitely need a sandsifter as well, thinking about getting a goby and a few Nassarius snails. I know my rock has small bristleworms and maybe some spaghetti worms hitched a ride over from the old tank.

I also really want a wrasse of some sort. I was thinking a Yellow Coris, Sixline, Mystery, or maybe a smaller Haliocheres species. I'm open to suggestions if anyone can think of something cool!

Right now I'm letting the corals relax a bit and tracking the overall health of the system to make sure it's okay. Once it's settled a bit I'll put the aquascape back together completely and start planning for additions.

And if you're wondering where that Hammer colony went... It fell while I was working on the 20 gallon and split in half, so I went ahead and fragged most of it. The 20 gallon is now full of hammer frags that I have to deal with, so if you're in the Pensacola area let me know and we can do some trading if you're interested.

nautical_nathaniel · Jul 31, 2026

It's been a couple of weeks, here's an update on everything:

I've rearranged a few corals and added a couple new fish and corals to the tank.

I produced around 19 frags of Rainbow Hammer coral after my large colony broke apart while moving everything. I kept the largest frag and traded the rest for a handful of different corals including a NY Nicks Torch, Sonic the Hedgehog Galaxea, and a couple of mushrooms I put in my 20 gallon for my Zoas/Anemone system. Probably not a good trade but I got rid of all of them at once and that's good to me haha

Bilbo, my Starry Blenny, likes to rest against the overflow a lot, which drives the ATO haywire, so I've added a little basket in front of the overflow to keep him off of it. So far that is working pretty well but it's a bit unsightly. Thinking about getting a 3D printer to build something more permanent (Costco has a good deal on the Bambu A1 Combo that I've been eyeballing for some time now).

Here's a list of the current livestock:
Flame Angel
Blue Devil Damsel
Starry Blenny
Strawberry Dottyback
Golden Head Sleeper Goby
Timor Wrasse
Flame Shrimp
Handful of Hermits
Bumblebee Snails
One really old Trochus Snail

The dottyback, damsel, and flame Angel all might be re-homed soon. I'm sorta tired of watching everyone beat each other up all the time and kinda want to go to peaceful nano fish only. The flame Angel is the only one I actually bought with intention (the other two came with the 40 gallon when I bought it off Facebook Marketplace) and he's been a great fish but he's starting to nip corals a bit and bullies everything in the tank including hermit crabs.

The Goby and wrasse, which I ordered a week ago, have been settling nicely, however, they came in jumbo sized. The wrasse is a solid 5-5.5 inches long and way bigger than I was expecting (listed online at 2-3"). The Goby is also a full grown stud and has 2 inch long streamers coming off his dorsal fin. Not sure what I'm going to do with these fish long term. They would be great for the 120+ Gallon I'm planning on building eventually but that might be another year or two off.

For the time being, I've ordered a trap and acclimation/holding box for the dottyback and damsel and I'll try rehoming them among the local reefers or seeing if there's a LFS that will take them.

nautical_nathaniel · Aug 4, 2026

This morning I moved my glass cleaner out of the corner where it normally stays between water changes and I found this:

Turns out my fat Starry Blenny Bilbo was actually gravid with eggs

Now I kinda want to find her a boyfriend but I'm definitely not setup to breed and raise baby fish. Maybe it could be a future project when I have a workshop and fish room going.

JumboShrimp · Aug 4, 2026

Did you say those four baskets in the photo do or do not fit your current tank? Because I recognize them as fitting an AquaTop brand tank, if that info is of any use to you. Best wishes.

nautical_nathaniel · Aug 4, 2026

JumboShrimp said:
Did you say those four baskets in the photo do or do not fit your current tank? Because I recognize them as fitting an AquaTop brand tank, if that info is of any use to you. Best wishes.

They do fit, I currently have them in the middle chamber on the back of the tank. From what I can tell, that chamber was designed for them because all four stack to just below the height of the leading baffle into the chamber.

I still haven't found anything to fit into the first/overflow chamber that would be the location for a filter sock or filter cup on a newer AIO aquarium. That chamber is sitting empty right now and my heater is in the next chamber, so."dirty" water flows through those two chamber into the middle chamber with the media boxes.

So far though, the first box being filled with filter floss (the regular blue and white stuff) has been doing a pretty good job at providing mechanical filtration for the whole tank. There's just a little detritus buildup at the bottom of chamber one and two that I can easily siphon out.