Like almost every nano tank on the market with built in filter, the outflow on the Fluval Spec III and V is just a little to strong for most bettas. My solution up to this point was to stick a sponge over the outflow. This solution has two flaws. One, it works too well, circulation around the tank is reduced to virtually nothing. Second, it is rather large and if not quite an eyesore, it reduces light to plants directly beneath. I was setting up new tanks and realized I was running low on sponges, I had an inspiration, and realized I had been scavenging the wrong part of the sponge filters I have. A different part of the sponge filter makes a perfect little spraybar. Replacing the nozzle that comes with the spec with the spraybar-like part from the sponge filter results in good water circulation, but in an omnidirectional flow that does not bother my bettas. The narrow black tube is almost invisible in the tank as well, especially considering the black background of the Spec tanks. I imagine that a similar mod could be used on some other filters out there. This common little sponge filter breaks down into a lot of different little components. They happen to match the standard tube sizes used for almost all filters and I have at times with DIY projects or modifications found various uses for various ones. In fact the entire assembly fits on most intake pipes of other filters for a dual intake pre-filter. Parts that are swapped, the nozzle of the Fluval outlet, with the spraybar-like part of the sponge filter. My latest setup, an array of Fluval Specs. Found a use for this 48" light that was too weak for my 50 gallon, but works awesome above these small tanks.