It just doesn't work. Spill over out of collection cup is commonplace. Never get a consistent cyclonic action, or any action, in the chamber.

I purchased this for two reasons. 1. the cost, & 2. the reviews. As of now i regret purchasing this unit. The manual is pretty vague and the water level in the sump continues to fluctuate. I have cleaned this unit and made sure nothing is in it's way. it rests in the sump in it's own space. I am told there may be an air pocket but i am unable to find it. I have reached out to coralife with no response. my ato sensor continues to go off and i have to turn it if. it is a burden to operate this skimmer. i will be looking in to replacing it in the near future.

All in all very easy to set up. Is a big bugger though. The adjustment knob is VERY sensitive. I have poured countless gallons of water onto my floor by making a change and not sticking around long enough to see how much of a difference it made. I appreciate being able to hang it on the side of my sump but I finally decided to place it inside to prevent further mishaps. Operstionally though it does what it is supposed to do. It's also quite quiet considering how big the pump is.

This is overall a great in sump skimmer, this is the third one in 12 years, easy to use. But if used outside the sump be careful it sometimes does overflow / leak without warning. But it is a great skimmer.

This unit works well, and is easy to set up. However, it is very large for a hang-on unit. It will interfere with a hanging light setup.

I've owned the 125 gallon since 7/2016, and the impeller has already broken. Plus, the motor makes quite a bit of noise. When it worked, it was great. I highly recommend either a different brand, or at least have a back up if it breaks. Hopefully Coralife will replace it under warranty, but it looks like I will have to pay for shipping one way. Really not happy with that aspect of it. I will see if I can find a spare impeller, so if it breaks again.

I've had the 220 set up for a dry skim for about a month now and it works very well. It pulls nasty dark skim out. It took me about a week to get it dialed in the way I wanted it but that's normal for most skimmers. I run this on a 140 gallon system. I use this in sump so I cannot comment on the hang on feature. I will say it is very large and you may want to check clearance before you order. I rate it 5 stars right now but my opinion could change after time. But so far it has operated correctly and efficiently and I couldn't be happier with the investment.

Review/Discussion is about the 220G. Despite the productive criticism stated here - I like the unit, it is working well and getting out some foul smelling "Skimate". Between water changes, the installation of nitrate absorbing filter pads and the protein skimmer - my reef aquarium water is crystal clear, and has no odor to it. Read on. Several issues discussed here: 1) Items missing in Parts Diagram (but were with the product). 2) Instructions do not discuss the items missing in parts diagram. 3) O-Ring Treatment prior to assembly 4) Acrylic does not seem thick - I was very careful in my handling of the product, including how tightly I secured the collection cup to the main body. FYI - To minimize the possibility of leaks - there are two rubber O-Rings that the technical support said to put Petroleum Jelly on. First one is obvious where the collection cup is secured to the main body. The other one is the red air intake valve - that is leaking on my unit. This has to be pulled up to get to the O-Ring. This is NOT in the instructions - though to be fair - having worked on my home swimming pool - I saw the big O-Ring and thought I should coat it with something but did not, I did not know about the valve O-Ring. Product is working well and was easy to configure. That being said the first issue regards the instructions that came with it. The parts diagram is incomplete. And instructions regarding the missing items are missing. There is fortunately a picture of the completely assembled skimmer on the instructions. Items missing on parts diagram regards the venturi valve (separate cylinder on 220G), tube connecting it to the impeller screen cover. This items supplies the air that is mixed with the water on intake. Missing in the instructions is the following: 1) Discussion of the setup of the Venturi Air Supply, connecting tube and valve. 2) Discussion on O-Ring treatment. I set the unit up - got it going (easily enough) and did some work for a few hours to make sure all was OK knowing I would be in the next morning. Came in next morning to find a small puddle (less than 1/4 cup) of water that had leaked out - mainly from the air valve adjustment. I called the tech support number who was very good at managing the issue. All I had to do was email the product purchase email from drsfosterandsmith.com and my shipping info. They are in the process of shipping me a new skimmer body. Coralife may save themselves some return issues by at least addressing the O-Ring in their instructions and possibly including a small packet of lubricant/petroleum jelly. I will address the O-Ring lubricant issue tomorrow and see if it takes care of the leak. Meanwhile I have a small bucket underneath the skimmer. Meanwhile our clients that come through our office see it and ask what it does (I don't have a sump tank setup yet - that is a project for this summer!). They think it looks cool and space-age.