If you are looking for pumps that have manufacture defects (acknowledged by the company making them via email to me), clog all the time, and are COMPLETE GARBAGE, then look no further. They are horribly designed. I have 5 of them. Trust me, I know!! The fins rub on the end of the shield causing groves and motor seizing. Calcium builds (due to poor seals) up on these from the inside over the course of about a week or two and will cause the pumps to stop turning. They clog up so bad that the bushing (the part that's supposed to act as a type of bearing) will literally start turning in the rubber sleeve that holds it. It will turn to the point that the bushing and rubber basically wear down to nothing. Additionally, the pump housing rubs against the magnet causing slices of the magnet (metal, which is HORRIBLE for an aquarium) to rub off and get into your precious water. It leaves groves in both the impeller magnet and the motor housing, which cannot be good for longevity or functionality. I have been emailing the company (Coral Vue...who is clearly full of illogical idiots) for months now, and all they offer is a store credit so that you can buy more garbage products from them that will fail and possibly cause your entire system to crash. Oh and they won't give you any credit until you send them the product back (meaning you have to buy a replacement pump while you wait for however long they decide they wish to take to credit you). So, unless you like spending hours and hours every single week or two cleaning your pumps, I HIGHLY RECOMMEND THAT YOU DO NOT PURCHASE ANY PRODUCTS FROM CORAL VUE!!!!!