Gulfstream Tropical AGU00528 Ista Max Mix Co2 Reactor for Aquarium, Medium

This reactor beats out your standard CO2 diffuser by LEAGUES. I have a 15 gal heavily planted tank with high lighting. I was running 1.5 - 2 Bubbles of CO2 per second with my diffuser. I installed this, and not only does it get my CO2 levels up much quicker in the morning, but ive turned my bubbles per second down to 0.5 bubbles per second or less!!!!! Its going to pay off its own price in one single months worth of CO2 saved. Get this product over a diffuser if you have a system that supports it.I have the Fluval Flex 15 Gal, and i use it completely submerged in the pump section of my tank. Works great. Fits like a glove

I have an ista max mix medium and for the money, it's not bad. You'd be hard pressed to build something more professional looking for that price. I power it with a powerhead since I don't currently have a canister. Based on the concerns of them leaking, I've seen people usually put additional small hose clamps or something on the connection points. Be careful not to overtighten since it's only plastic and may crack. Because of the leak concerns, I just put the whole thing inside my tank and semi hid it with plants. I understand that this is not optimal for some people so it's something to think about.The other issue with it is since the impeller inside is critical to the mixing process, you need more flow to spin the impeller faster if you want to push your CO2 injection rate higher. Otherwise, CO2 will build up on the top section of the chamber where the impeller is, the water level will be lower than the impeller, and then it'll just stop mixing. I experimented with different powerheads until I got the one that was powerful enough to do the job. If you go that route, I recommend the Hydor Pico line. They've got a decent amount of power and more importantly, they're whisper quiet! 180GPH is probably the least I'd go with. Here's one with a claimed 300GPH. Hydor Centrifical Pump 300 All-Purpose Pump for Aquariums and Terrariums 300 GPH - Original Pico Evolution 1200 Any less, and you'll be restricting how much CO2 you can mix in. The pico also has adjustable flow so if you discover you want less co2 and slower flow you can do so. Finally, like the reviewer before me, Brandon Miller, I discovered that there was also a little extra flashing (imperfection) from the moulding process inside the intake tube that I had to file down. This was restricting the water flow into the chamber. So even though I had a powerful powerhead, all the flow was being restricted, and it was not mixing in as much co2 as I wanted. For the first few days from when I first got it until I found the problem, I thought the reactor was faulty since the impeller refused to spin properly.Update: After a little over a year, I upgraded my filter to a Fluval 206 and plumbed the output directly into this reactor. The increased flow is actually causing a ruckus in the reactor because the impellers are spinning too fast and unevenly. I ended up taking out one of them and letting the top section of ride without an impeller. With sufficient flow, I don't see a problem with the mixing and now it's pretty quiet. You can only hear the trickling of the water mixing with the bubbles. If you do NOT have sufficient flow for the amount of co2 that you're injecting, then don't do this, because you won't have enough mixing going on, and you need the impeller's help.

Works really well, and you can see it working. The only problem we had was the bottom of the reactor leaked initially. This was easily solved by applying petroleum jelly to the threads and then screwing it back on.

When I took it out of the box I noticed a vertical crack of about 3 inches long. The crack didn't go all the way through so I kept it, and so far it is working without leaks. I would have sent it back but I needed to get my CO2 going. The unit comes with a number of adapters for different size hoses and I had to use a couple of them with my eheim hoses. I did experience a leak on the top connector because the hose, even with the adapter, isn't as tight as it should be. Next trip to the hardware store I'm getting some hose clamps for added safety. As for function, it works perfectly. I can't hear it running but it spins constantly and my drop checker says I'm getting good CO2, plus my plants are pearling regularly. My reactor is seated at a 20-30 degree angle because I haven't been able to keep the suction cups secure and the stiff hoses put enough pressure on it to shift it. I gave up trying to keep it totally vertical and it hasn't had any effect that I can find.Overall, I'm happy with this reactor but be sure to check it closely when it arrives and consider the addition of hose clamps.

Do yourself a favor and buy a higher quality reactor or make one yourself. This Max Mix reactor is made very poorly with cheap material and IT WILL LEAK from every possible place. First it leaked from the bottom, so I had to silicon that shut. Then it leaked from the intake and outtake, so I had to add plumber's tape and hose clamps. Then, just when you think there is nowhere else for it to leak, the internal tube that spins the bubbles loses its seal at the top, so the CO2 bubbles bypass the entire purpose of the reactor. And I can't get in to try and seal that, because I already had to silicon the bottom shut (which was just absolutely gushing water out of the seams). I consider myself a decent tinkerer, but this product is un-salvageable. I've went ahead and built my own reactor from PVC and an old gravel vac. Please do not give this company your money. It should not be sold on Amazon.

I bought this after trying out a GLA inline atomizer. The inline atomizer developed a crack and the manufacturer ignored my repeated attempts at contact. This product is well made, but will require additional hose clamps to secure the hoses. Simple design, but very efficient. Makes a bit of sound, but not too bad. I'd recommend checking out youtube for installation videos.