The MiniMax Sump is a new media reactor from Innovative Marine which is an interesting take on the concept. This new device and its novel operation is a fresh new direction for small media reactors, and it didn’t take us long to really like it.
Innovative Marine has always been especially focused on all in one aquariums, and their MiniMax Reactor is optimized for this with its hang-on form factor. What we love about the original MinimMax reactor is the ease of servicing it, by simply lifting the inner chamber out of the reactor, without ever having to unplug anything.
The combination of a nested sleeve is also present on the MiniMax Sump, allowing users to both change out the media and to dial in the flow rate with a simple twist. The biggest improvement in the MiniMax Sump reactor is that the wider yet shorter dimensions makes it much more suitable for use under the aquarium.
When we used the long and skinny original MiniMax, in some short stands it was a tricky affair to pull the sleeve all the way out. Also the hang-on form factor was not especially steady standing up, nor was it meant to me, but the wider footprint of the MiniMax Sump completely rectifies this.
Also, it might seem like a small detail but the MiniMax Sump reactor is equipped with a powerhead that draws only from the base. This is the same pump that is paired with the Midsize MiniMax Reactor but Innovative Marine could have absent-mindedly gone with a different design, but they didn’t.
This means that this reactor will run in even the lowest of sump water levels without drawing air. And although you can adjust the flow rate simply by twisting the inner sleeve of the reactor, if you want an even lower flow rate you can also adjust the flow rate of the feed pump.
Also, at first it seems like that short little chamber couldn’t hold much media, the wider diameter actually has a deceptively larger volume than you might think. The 380 ml chamber is more than enough to react an appropriate dose of activated carbon, GFO, or biopellets for upwards of 100 gallon reef tanks.
Some readers may disagree but our chemical filtration philosophy is to use less and change it more often. The small footprint is also ideal for placement in tight sumps, and we could see it being more practical to have several of these with different medias in a large sump, rather than have one bulky and hard to service media reactor. 
At first we weren’t sold on the dual O-rings used to secure the lid of the inner sleeve. Surely one o-ring is enough to make a tight fit, but the added snug fit is important for turning the inner sleeve to adjust flow rate, without which you might just spin the lid without turning the sleeve itself.
The final subtle but important improvement that the MiniMax Reactor has over its predecessor is an improved flow adjustment design. Before you could spin the inner sleeve of the MiniMax freely, and sometimes it was hard to know whether you were rotating towards higher or lower flow.
With the new MiniMac Sump reactor, a mechanism only allows a certain degree of rotation towards maximum or minimum flow. This way you’ll always know how it is set, without having to actually see the alignment of the exit holes.
With all these improvements, there’s no doubt that the MiniMax Sump reactor is one of the best that you can get. Surely some GFO and Carbon-happy reefers will opt for a reactor with a larger volume, but for most of us, the capacity of the MiniMax Sump reactor is more than enough.
It’s quite a delight to see Innovative Marine translating some of their best work in All in One aquariums to use under the sump. With Innovative Marine having made a big mark on all aspects of the AIO market, we have to wonder if the company is branching out into reef ready tanks and reef gear, if so, the MiniMax Sump Reactor is a step in the right direction.
