| I'll second the Tunze streams. Not only do they break easy, but both of mine did not quite snap together so it wasn't too hard to pull it apart (though not without breaking a tab or two). I just glued my second one right away befroe waiting for it to break.
My other qualm is my Hydor Theo heaters. The scale is about ten degrees off on all four that I have! I bought this kind because they are the shortest ones per watt that I found. They do hold the temp steady, but you are going to be out of luck if you want the water cool enough for sea horses or somehting less than a reef. One is all the way down (I think 69 or 70 is the limit) to maintain 80deg temp. | 
