Review on Enhance Water Flow and Circulation with Hydor Koralia Evolution Aquarium Circulation Pump by Lena Marckese

I have a deep tank (36 inches) and I kept dumping dirt on the sand which looked ugly and turned the sand brown or green. I installed two of these, one on each side of my coral. The central part explodes. So far I've come away far from the amount of junk I had before. They have been working with the Hydor wave generator for 5 months without any problems. Rubber seal to minimize vibration and noise. The rubber seal is secured to the base with 3 rubber O-rings, each coin sized. I once tried to remove the pump from the side of the tank and it detached from the base and 2 of those tiny o-rings fell to the bottom of the tank and were never seen again. The company offered to send me a few but suggested that if I needed it I would contact Ace gear immediately. I did and after $4 I was back in business. . (They're 60 cents each, I bought them extra to keep in my parts bin. They work well. Nearly silent and have been very reliable so far, hence deducting 1 star for the basic design and doesn't include a couple of extra o-rings in the box .