There once was a time that every serious large reef tank was on track to become outfitted with a closed loop for providing water flow throughout the aquarium. Right before any kind of propeller pump became not only an option but THE option, there was powerheads in the tank, or a purpose built closed loop system.
If a typical tank has an ‘open loop’ where water is returned to the tank from a centrifugal pump but the loop itself is open where the water drains down and flows into the also open loop, then a closed loop is completely sealed from the point it exits and reenters the display tank. While we might have some massive propeller pump options these days, they are very expensive and require a lot of room inside the tank, not to mention all the cords and the hassle of removing them from the display for servicing.
The biggest drawback to a closed loop is that the aquarium has to be custom drilled and the plumbing has to be installed before the tank is built, it’s a reef tank feature that you have to commit to before set up. The sad part of the sequence of events is that we never saw a mature development and perfection of how closed loops can work optimally on a reef tank, which is why we decided to go this route for our largest reef tank ever, the eight foot, 400 gallon ‘Hardline Reef’ built by planet aquarium.
As you will see from following our own installation of the dual closed loops on this tank, this approach to creating water flow is not a shortcut by any means, it’s not necessarily cheaper either. We’re doing this not only as a reef building exercise but also to avoid seeing any pumps or cords inside the tank, although that doesn’t mean we won’t have some challenges trying to hide the inlet and outlets from said closed loops.
We took our sweet time enlarging the factory-drilled holes in the bottom and wrapped the actual external plumbing exactly 13 months after receiving this tank but now that the critical foundation of water flow has been provided, things will be moving much faster on this tank here on out. As mentioned in this vlog, we will be putting in a lot of effort to bring our viewers along the build of this tank in granular detail because building this unique aquarium system will be a fun learning experience for all involved.