Successfully plumbed macroalgae tank into existing AIO reef tank

bmercier · Feb 17, 2026

I wanted to share my final build of plumbing a new macroalgae tank into my existing 25 gallon AIO reef tank that's been successfully running for almost a month.

After some conservative estimates during planning, I went with a 6 gallon tank from Amazon. I calculated this volume would give roughly a 1"-1.5" clearance from the water line to the rim in my main display with the return pump off. I also used the Herbie overflow method with an Eshopps Eclipse S overflow box and the 14w Hygger full spectrum clip on light.

To raise the macro tank above my reef tank I made a custom stand following videos from The King of DIY on YouTube.

For the macro substrate, I used a base layer of Ecosystem Miracle Mud with CaribSea Arag-Alive Special Grade Reef on top.

Finally, I wrapped up the build (for now) with an order of live rock from Tampa Bay Saltwater and macroalgae I'd been growing in my main display.

eleslie3 · Feb 17, 2026

Nice job

Rshahnyc · Feb 17, 2026

Very cool. Also wondering if you could’ve just done a MAR from Tunze. Wouldn’t be fun visually nor have a sand bed though so if you were looking for a copepod area this is probably the right way

CHSUB · Feb 17, 2026

I did similar. Nice work…

bmercier · Feb 17, 2026

Rshahnyc said:
Very cool. Also wondering if you could’ve just done a MAR from Tunze. Wouldn’t be fun visually nor have a sand bed though so if you were looking for a copepod area this is probably the right way

I had previously turned the middle chamber of my AIO into a mini refugium with an IM ChaetoMax light attached to the back that's been working wonderfully for about 6 months. With my tank running for almost 2 years and in a good spot, I really didn't want to start over from scratch with something bigger or worry about maintenance on two separate systems. The goal of this build was to figure out a way to add water volume for added stability, display some cool macros, provide further safe spaces for pods, and just generally expand on the ecosystem.