MarineLand Magnum Polishing Internal Canister Filter, For aquariums Up To 97 Gallons, 10.5 IN (ML90770)

Powerful little filter. Bought this for a 55 gallon tank cleared up in hours. Read a lot of complaints about noise but if you fully submerged the filter as directed it's whisper quiet. If you leave the top sticking out of the water it makes a rattling clicking noise. I'd be careful on smaller tanks it moves a lot of water.

So far I have been happy with this purchase. I purchased it for my 75 gallon reef tank with a few fish and some soft corals. The tank has live rock and a protein skimmer, and I have tried and abandoned a number of different hang-ons (didn't work), and cartridge filters (too risky). Living in an apartment where any water spill will run down below me, I just could risk using anything outside of the tank, which is one of the reason that I got rid of my sump when downsized my tank size. However I clearly needed some type of mechanical filter.So without much hope, I decide to try this one, without having to make another big investment. I have been pleasantly surprised that using the cartridge filter I have have had considerable success in cleaning up my tank and my corals look much healthier.Pros:The whole thing fits in my tank through it is fairly big, which may be a factor in anything smaller.I have been able to clean and reuse my original filter several times, through I have also purchased a 2nd filter which I rotate. Filter life varies but is now approaching 3 to 4 weeks before the filter become very noisy.The flow rate is very good and I use it to help move water around my live rock.It is fairly easy to clean, through kind of a pain to move in and out of the tank.Replacement filters are not expensive and they can be re-cleaned often. I am still using the first two after 6 months of use.Cons:The filter gets very noisy as it clogs which depending on how often you have to clean it may be annoying.The filter is fairly large making it suitable for a 75 gallon or larger tank. It might be OK in a 50 or smaller tank depending on how much room you have.It has a pretty good flow rate, which may or may not be a problem, or a plus for you.

TL;DR: Major design flaw. Impeller is not designed to properly sit in the motor unit and just grinds unbearably. Taking apart and cleaning (a nuisance at best) will temporarily resolve. Seems impossible to order replacement impellers so if you need to fix it you're SOL unless you want to drop money on a new one, which will inevitably have this issue again.I've been a fish hobbyist for over a decade, and in that time I've concurrently kept dozens of tanks with different species, sizes, water types (fresh, salt, brackish). I've even worked in the trade before. When I moved into my house a year ago I decided to get a large show tank for the living room, and decided to go with an internal filter because on average they're easier to maintain than external canisters and less ugly than overhanging ones. I've used many different brands for my other tanks, mainly Fluval and Aqueon, but I went with a Marineland for this one because they used to be really good.This thing will be whisper-quiet right until you're passed the return window (convenient!), and will do a good job keeping your tank clear. Within a month or two, the filter started making a grinding noise, and per manufacturer's instructions cleaning out the impeller blade helped for a short while. It wasn't long until no amount of cleaning, weekly or daily, could fix the horrible grinding noise that this thing would make. Seriously, I'm great at tuning out sound but this was god-awful. I felt embarassed to have guests over it was so bad.I concluded after taking apart every inch of the motor that the impeller blade that I received was just faulty, but as of writing this review YOU CANNOT GET REPLACEMENTS, as looking at their website it appears they've been out of stock since pre-pandemic. They're still selling the model, but you cannot buy the impeller separately, which means the only option is to buy a new unit, which is ridiculous company practice. But don't worry! Customer service responses on their Q&A indicate that the part will be coming back "soon." This is, of course, the same response that you'll see if you keep scrolling to customer questions from 2+ years ago. They're not intermittently out of stock, because you can see multiple people have been patiently awaiting replacements for all that time.I bit the bullet because I assumed I just got a bad one, and I didn't want to completely change my set-up. But less than two months in to this new one, it's already making the grinding noise. I'm writing this review with the unit completely stripped and disassembled in the other room, and after doing extensive research it seems like this is a common problem for this model. Their company page for the impeller is littered with people complaining about this issue and canned service responses indicating "it just needs a good clean." I've taken apart MANY motors, and the issue is not that it needs a good clean. It's not even that it needs some oil (tried), some o-rings to soften the impeller rod ends (tried), or a good flush (tried). You'd have to re-cast the piece entirely and tweak the housing to get it to work as intended. My partner, handy with bigger motors and mechanical parts, took one look at it spinning and concluded the same before I even managed to get it off the motor housing.I know this is long-winded, but honestly I'm just frustrated that it seems like they're willfully ignoring a severe design flaw, and seem to be fine selling more units of this without offering the replacement parts they must know will be needed at some point. Shame, but I don't think I'm going to buy Marineland ever again. Marineland used to be my number one recommendation to new hobbyists but even though set up is simple, maintenance of this model is NOT beginner- or consumer-friendly. Blegh.If you get this model, just use it for infrequent water-polishing (note, it doesn't come with DE or a polishing medium, so you still would have to get that separately, and ensure that it's the right size for the housing unless you want dirt soup in your tank). Don't purchase it as a filter.