Review on Hydor Pico Evolution: Versatile Centrifugal Pump for Aquariums and Terrariums by Amy Lindsey

This is an excellent pump for low flow applications. I currently own two of them. One is in my 12 gallon (3ft) tank to distribute the CO2 to the back of the tank without creating excessive flow. He does his job very well. I hid it behind a rock and you wouldn't even notice if you didn't look for it. Another one I used in a homemade canister filter for a 2.2 gallon shrimp tank. It has enough power to effectively filter the water without sprinkling my shrimp down the backflow. I've seen several reviews that say the pump is noisy or rattles. In fact, the pump runs almost silently, but sometimes I hear a knock. I believe that's what happens when a small piece of dirt gets sucked into the pump and gets caught on the impeller. When that happens, I just unplug the pump and plug it back in. That seems to be all it takes to clear debris and get the pump running quietly again. When this happens, however, you won't hear the rumble unless you're standing directly in front of the tank where the pump is located. I gave this pump 4 stars instead of 5 for a reason. The point of this pump is that it is small so it can be used discreetly in small aquariums and the pump itself is quite small measuring 4.25 x 2.75 x 5 cm (approx). However, to attach it to the aquarium pane, you must attach it to the bracket provided, which has 4 suction cups attached. With this mount in place, the total footprint of the device is (approx.) 7 x 10 x 7 cm. That's a huge difference which in my opinion defeats the purpose of the product. I fixed this purchase by deciding not to use the mount at all. Instead, I took suction cups and Krazy glued them directly to the block (yes, Krazy's glue is safe in the aquarium once it dries). This is a great little pump for summer, but the dimensions given are misleading. Hydor made a wonderful little tank pump if it can be used without a mounting bracket.