I have always believe and read that a free flowing reef tank is a better choice vs one with use of filter sock. After 2 years of very high matainence schedule with water change, cleaning algae off the glass....etc..etc, I decided to try a filter sock. My only means of filtration at the time was my skimmer and water change. After using it for about 2 weeks, I am a firm believer of using it. I change the filter sock about twice a week and notice a big difference is water clarity, much less algae (I only clean it once a week vs 2-3 times a week) and my fuge stays very clean. I should of done this a long time ago and would of save me a lot work! :rollface: