So I read many reviews on this product and watched youtube videos on it as well. Everyone said the same thing and shame on me for not following my gut feeling. I've been in the aquarium hobby for years and this was my first attempt at setting this up the way its supposed to be done according to the directions. First of all, everyone said it leaks. Well, it does, and from a few places. The hose input and output leaks, the bottom screw on access point leaks and overall this is a cheaply made crappy product. Now, am I saying it doesn't work? IDK, but its not working for me simply on the fact that I shouldn't have to completely seal and bond every point of this contraption and use hose clamps which still leak. The directions may as well be a pop up book with no words, unless you can read some vague chineese symbols if the directions translate into English. It never says what appropriate size hose to use, I tried 1/2 inch and it fits fine, but still leaks. 3/8 seemed too tight. 5/8 too big. The suction cups that are supposed to hold the unit mounted to the tank aren't even designed for this unit. The suction cup plastic nipple molded into the unit that is supposed to go into the suction cup hole, for one isn't big enough, for two even if you did get the nipple in without breaking it off it won't be held by anything inside of it because there is no inner lip that catches the fatter part of the nipple to hold the suction cup in. Instead it looks like there needs to be a larger bracket or slot that the suction cup tip slides into a hole and then holds the unilt to the suction cup, but there is surely no bracket for that whatsoever so that deems the suctions cups useless. Just a P*SS POOR design on that end. As for the overall functionality, from a design aspect the concept seems cool and would probably work as others have mentioned, but what does your time cost you? I spend about 2 hours trying to get this thing hooked up and running which took about 30 minutes at most between the hoses and my filter etc, but then the next 1.5 hours it took me to "ATTEMPT" to get this thing to stop leaking. I tried teflon tape, no go. Then added a bit of plumbers dope, no go. Cleaned that off and aside from probably needing to silicone the hole thing shut for good, I stopped there. Then came the hose ends leaking. Every attempt to see how the water was leaking and to get it to stop was failed. And trust me I've remodeled houses and I do everything from plumbing to electrical and this thing doesn't serve its purpose. This needs to have barbed tips to hold the hose tighter than not and should come with some sort of hose clamps or even really secure zip locks if and when the correct hose that "they suggest" is used properly, but oh yeah they didn't do that. I don't feel I should have to set up metal hose clamps on a product like this. Oh, I forgot to mention for the little while that this was running the impellers would only spin when the unit was in a horizontal position. The directions say to keep it in an upright position at all times, YEAH RIGHT!! Everytime you put it in an upright position the impellers stop spinning. On one of my leak fixing attempts I took the main inner shaft out and it cracked too. Its like having an eggshell inner tube, instead of a nice rigid plastic durable inner tube that should be able to last. The plastic impeller blades are crap too. Overall this was a huge waste of time and money and I don't care how many people had to "JIMMY RIG" this thing to get it to function properly, but right out of the box this thing was a lost cause. If you are that serious about diffusing CO2 then I suggest taking more time to figure out another way instead of this as you may spend less time fussing with it, or be a bit creative and find a way to mimic this simple design if it works so well and build your own unit. I'm pretty much done with this plastic hunk of cheaply made chineese junk. I'm sure if an american company were making this it would have some sort of better standard, at least I would hope so. I'm not going to bother with customer service or returning it etc because at this point what are they going to say? Well, you modified it so it voided the warranty! Well, duh, no matter who you are or what you are using this for you are going to have to modify it and tinker with its major major flaws of design, material, and functionality so basically your warranty is already void before you purchase this. I usually give every product a fair shake, but this one by far is a total bummer. I only gave it 1 star because it arrived and was in a new box. Whoo hoo!! That's about all you will cheer for with this one. Like I said, I'm either going to have to make my own unit or pretty much settle on a ceramic diffuser that only costs a few bucks compared to this crap. I wouldn't have paid 3 dollars for this thing at a flea market if I knew this would be the case. I think Amazon needs to take this one off the website as it requires major mods and a waste of time. New products that boast what this one boasts should not need to be modified or re-engineered in any way or form and if consistent leaks were the issue it should be a simple call to replace a faulty unit as it was made faulty. Seriously, if this review hasn't changed your mind then be my guest and give yourself a headache and thin out your wallet a little because that's about all I can say you will accomplish with this one. I'll make my own!! Complete waste.....and probably an outstanding concept and design in what it's supposed to do "if it worked" and was made with better material and simple design details were some sort of concern to the people making this. This looks like some kid's science fair project that he was making out of his garage in plastic molds with zero quality control and product testing. but aside from that this thing could have come in a cracker jack box and been worth more. JUNK!! Amazon, stop selling this product. I love you guys, but seriously this one is a joke overall. I don't want to be vulgar, but I've had "protective latex gear", if you will, last longer than this.