OASECrystalSkim 600 Surface Skimmer for Freshwater and Marine Aquariums – Compact Internal Filter for Film Oil and Debris Removal, Quiet, Adjustable Flow, Shrimp-Safe, for Tanks up to 160 Gal / 600 L

The best tip is to read the instructions! It will tell you how to install and adjust the flow. Choose the lowest flow during the installation. That will help you to adjust the place you will install according to the water surface and avoid the skimmer to suck air. Then, if you wish, you can adjust to a higher flow slowly. The outlet of the water is on the bottom of the unit, so that's another reason to have the flow on low in the beginning, to observe the substrate you have on the bottom of the tank. If you put the flow too high and the skimmer is located too close to the substrate, in a low/small tank, for example, you will blow the substrate off! The skimmer doesn't need much flow to operate amazingly! I have it on the lowest flow setting for my 75 gallon tank. It will remove the surface scum in couple of minutes! It's construction is perfect and it works amazingly when installed correctly! The included tweezers is to remove the top grid protection and the blue sponge inside to clean. I am not going to use the skimmer with the included suction cups. I used some cable ties and attached it to magnets. The wire is long!! Very nice! I love this product!! If you follow my instructions in regards to the low flow in the beginning you will not have the micro bubble problem some people observed and complained. One last tip: make sure you aquarium is on constant water level, replacing the evaporated water daily, to make sure the skimmer won't suck air when the water level drops due to the evaporation! This skimmer is one of the very best I've tried, if not the best. Much easier to clean than all the others I've tried! love it!

This worked really good within minutes of being installed in my 10 gallon but I need to say this - Do NOT get this skimmer if you have a Betta in your tank!> Even on the lowest setting it is too strong for them - recommend a HoB filter with a skimmer attachment or included.> I put this in the 'dead zone' in my tank and it worked as advertised; clearing the surface film and getting water moving below the skimmer and creating a flow at the bottom of the tank.> I did not test out the highest setting since the lowest was too strong; I am going to keep this and use when needed until I find another HoB filter (as mentioned above.)> Flow needs to be adjusted without the top pieces are attached

The media could not be loaded. My only criticism of this would be when it gets some leaf matter or plant matter caught up in it, it will make a loud spitting dispersion of water, which I think can stress fish if left on attended. I love this product for taking some surface skim off the water every few days, or as needed, which it does very well and very quickly. It works great in my taller tanks but not necessarily in my 16 gallon betta tank, unless I keep it on low. I do wish there was a smaller model for smaller tanks and perhaps , it would disperse the water down and out using a deflector of some type. If it is too close to the bottom of your tank, you’ll need to consider the downward force and how it may affect things inside the tank, including gravel, mulm and other debris.It runs completely quiet when it’s clean and free of debris and only presents a problem if you happen to have some floating plant matter on the surface that gets sucked in. My Betta fish are completely safe around it even when swimming right up to it due to their curiosity.

This skimmer is small, quiet, and really does the job. I've only been running for about an hour, and the surface of my 40 gallon tank is crystal clear already. I think I'll just run this about 2 hours a day, if this is how effective it is. Very satisfied with the performance and the reasonable price.

I’m super upset, the product pretty much Killed my betta fish.Worked fine, it did what it’s supposed to do, I only plug it when it needed.However my fish got stuck between the product and the glass of the tank, idk for how long he was there because it was a super early work day and lights weren’t on when I left.Came back to him stuck, I panicked and as soon I took the suction cups he float lifeless.If you guys care for any feedback I would suggest maybe a different cups, ones that won’t get too close to the glass for little fishes like bettas.I loved this fish like all my others but the fact of knowing he most likely were suffering makes me extra upset

Wow—what an incredible little powerhouse! This surface skimmer has completely blown me away. I installed it today on my brand-new 75-gallon freshwater planted aquarium, and within minutes, the difference was astonishing. The biofilm and surface debris vanished almost instantly, leaving the water crystal clear. It's efficient, quiet, and works like magic. If you have a planted aquarium, this is an absolute must-have. I cannot recommend this brilliant piece of equipment highly enough—it's a total game-changer!

This unit certainly skims the film from the surface of the aquarium . . . . if the water level is perfect! When water level changes by 3/16" or so, the unit starts to suck air and becomes very noisy. You have to adjust the height of the unit or top off the tank water almost daily. If you like to fuss around a lot, this unit is for you. I prefer the cheaper unit that is much more forgiving of water level changes and has a larger sponge filter volume. This unit has a pretty small sponge filter.

Best skimmer ive ever owned, if you understand how a skimmer works then you'll agree. The other comments saying "it doesnt work or having micro bubbles have the unit set up wrong", because they have the device way too high sucking air thru the intake and claims its difficult to figure out. <<DO NOT LISTEN TO THEM.. Its a great addition to your aquarium. It skims like a champ and has a clear guard around the float to keep bigger debris from blocking the intake.. Listen to someone who is on their 50th aquarium, not their first aquarium... I have 25 years of experience in the freshwater and saltwater hobby, i can tell you now that this is a well thoughtout device. Everything esigned in Germany works as intended without user error...