OASE CrystalSkim 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

One morning I noticed that thin oily film forming on the surface of my tank — the kind that makes even crystal-clear water look dull under light. It bothered me more than it should have. I added the OASE CrystalSkim 350 Surface Skimmer, and within a short time the surface looked noticeably cleaner and more reflective. 🌊 Surface Film & Debris Removal This is where the CrystalSkim really shines. It pulls in surface film efficiently without creating a whirlpool effect. Within the first hour, that hazy layer was mostly gone. Over a few days, the water surface consistently stayed clearer, which improved overall light penetration and shimmer. 🔇 Quiet Operation For something constantly running at the surface, it’s surprisingly quiet. There’s a soft hum if you’re standing right next to the tank, but it blends into normal aquarium background noise. No rattling or harsh suction sounds. 🔄 Adjustable Flow The adjustable intake is useful. You can dial it down if you have a smaller tank or sensitive livestock, or increase it for heavier biofilm situations. I appreciated being able to fine-tune it instead of dealing with fixed, aggressive suction. 🦐 Shrimp-Safe Design This was important to me. The intake design prevents shrimp or small fish from getting pulled in, and I’ve seen no issues with curious invertebrates exploring near it. That peace of mind matters in planted or shrimp-focused setups. 📏 Size & Fit It’s compact and doesn’t take over the tank visually. Compared to some bulky surface skimmers, this one blends in fairly well. It works for tanks up to 92 gallons, but it doesn’t feel oversized in mid-sized aquariums either. 💰 Value for Money OASE equipment tends to sit in the premium tier, and this follows that pattern. It’s not the cheapest surface skimmer available, but the build quality, quiet performance, and consistent film removal justify the investment if surface clarity matters to you.

I have multiple tanks and all but one will grow a layer of biofilm (the oily film) on the surface. I have tried two other skimmers and this one is by far the best. It does a great job at removing the film and is easy to clean. The main selling point for me is the outflow points downward instead of off the side. What I found with other skimmers is I had to turn up the flow rate quite a bit to get a good downward suction to remove the film, but this created wayyy to much outflow in the tank. This one does the job on the lowest sitting and since the flow points down, there's not much disruption in the tank. It's the most expensive skimmer but also the highest quality, you get what you pay for. It's the only skimmer on Amazon that has a downward flow so it may fit your tank's need better. This is the one if you want a skimmer that doesn't generate too much outflow.

I maintain several planted freshwater aquariums with a variety of aquascapes, and I own a few of these surface skimmers. This model has a nice adjustable flow, runs fairly quietly, and does an excellent job clearing biofilm from the water’s surface. However, it has a frustrating habit of catching on its own power cable, causing the unit to sit too high or too low in the water—both of which make it ineffective. I often have to fiddle with the cord and reposition the floating ring to keep things working smoothly. Still, for the price, it’s a solid value—just wish the cord management was better designed.

I got the Crystalskim 350 to help with the surface build up I was experiencing in my 75 gal aquarium. As others have stated, it’s not the easiest thing to set up. It is way too powerful. Even on the lowest speed setting and having the filter as far down in the water as it could go, I still was experiencing micro-bubbles. To solve this, I replaced the provided extremely coarse filter pad with a more fine pad that i cut to size. That solved the issue. Although, i expect this is going to lead to more frequent maintenance. My other complaint is the unit i received is grey, not black. Which is unfortunate because my background is black and i was hoping this would blend in. It doesn’t. Construction seems solid, it is quiet, and it made a visible difference in about 30 min. This is my first Oase product, so only time will tell. So far, it does what it’s supposed to. But since i had to modify a $35 surface skimmer, and i received the wrong color, i’m rating the Oase Crystalskim 350…3 stars. *Edit* The micro-bubbles came back. The only solution I can find is lowering the flow rate all the way down. Which reduced the filter’s effectiveness significantly. The filter is not capable of keeping the surface clean on its lowest setting. So its either a semi-clean surface, or microbubbles. I’m knocking this piece of junk down to 1 star. This is what i get for not getting a Fluval. If the Fluval sk400 was easier to find in America, I would have never went with this hunk of crap in the first place. Avoid this purchase.

Bye bye duckweed! If you have duckweed in your tank and want it gone, this is a great addition to that battle. You have to have patience, though. I got the 350 and I’m sure the 600 would’ve cut the time it took but it still worked great. First, let’s address the bubbles that is mentioned in other reviews. Yes, it will cause bubbles but that is determined on how you position the mount to the water line. The further down you place the mount so the top is slid up some, you won’t have bubbles. But, if you want it to work like an air stone, move the mount higher. Second, duckweed removal. Don’t use the blue filter that comes with it. Put a small amount of poly fill in it instead. You will go through a lot but that’s better than trying to clean the blue filter each time. Turn your regular filter off. You don’t want that continuously pushing duckweed down into the tank. Fill your tank to the top of your trim if you have any. Scrape out as much duckweed as you can and remove any other floating plants you want to keep. Then just turn it on. It’ll suck up a ton of duckweed. When it gets full, remove the unit from the mount and tank before unplugging it. Unplug it first and all the duckweed will float right back in the tank. Move the unit around the tank when needed and make sure to scrape around the trim with your finger to loosen up and stuck duckweed. Lastly, take some water out the tank and you’ll notice more duckweed. Keep with the process and soon you’ll be grabbing random pieces with a net. Good luck! Lastly, the color is grey, the mount is very sticky, the unit is very easy to use and fits perfectly in the tank.

This is actually one of the best surface skimmers I've owned and to be fair to other manufactures has a lot to do with design improvements over the years. Some others I've used in small tanks are: Eheim Skim350 (excellent skimmer but not for small fish unless install custom netting over the inlet); AquaNeat (budget price, decent but not best); ADA Vuppa II (quality built, pricey, skims well, motor mechanism prone to failure). What I like about the Oase 350: excellent skimming, inlet/outlet designs, pricing, functionality.

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!

Edit- it can suck up the tiniest of shrimplets but have only found one dead one when I opened it to clean out the plant specks. There’s usually a few grazing on the sponge but they are easy to see and I use those handy tweezers that come with it to scoot em off back into the water. Happy with the purchase! (End edit) Built solid, easy to operate and setup. Good quality suction cups and bracket. Very small and compact. Using in a 10gal plantscaped shrimp tank with gravel substrate. Not recommended if you have sand substrates. Excellent with gravels. This is due to the downward water blasting straight down. The intensity of this downwash is based on how + or - you have it set to. My shrimps don’t mind hanging out under it for what it’s worth. I keep it set pretty close to minimum. Silent operation and versatile setup options to best suit your needs. The fine grills seem to be doing a good job keeping my shrimps out but letting the plant specks in (granted it has only been in a day so far but even if they do I’m not worried about em. They’ll be fine till I get to em. Maybe even happy!) I’ll update if anything changes. Note: I did replace the coarse blue sponge it came with for a much finer/denser sponge I cut from an extra foam piece I had from an old filter replacement. I was worried that the insanely difficult to deal with water-meal would be able to go through the sponge holes and go back into the tank. That’s the only mod I did and it’s because I’m using this to fix a problem of water-meal aka pond meal and it’s so much worse than duckweed. Smaller and *far* more prolific. This is making short work of it and for the first time in weeks, I have hope that I can actually beat this “plant” and successfully remove it for good. It’s proven to me to be pretty much the worst. With it taking over a fully stocked, heavily planted shrimp tank, a full breakdown and sterilize was not an option. Manual removal was an proving to be a mammoth exercise in futility. Now that it’s installed, I can’t help but giggle to see the green micro balls of doom get sucked up automatically. I was worried that they would float back up and out and back into the tank when it turns off due to the timer, but it seems the sponge I used traps and hold them perfectly. Rinses off in seconds. I have no qualms with this piece and overall I am super duper happy with this skimmer. It feels quality built and seems like the cost is appropriate. Long story short, This was the answer to a difficult question. “How to remove water-meal in a planted shrimp tank” And boy am I happy I chose this one! I have it on a timer to run for 30 mins every 4 hours. It’s super easy to clean. Just take the top off, use the included tweezers to pull the sponge up and out and rinse off. Easy as pie. No need to turn off, or even remove the unit for this. Great design. It seems like the designer actually knew what they were doing!!! Very rare to see these days. Very refreshing and hope it holds up over time. Super happy to see those micro plants get sucked up. I don’t want to tell you how many hours of my life I wasted with a cup trying to skim these out day after day, clear the surface and the only to find hundreds more the next morning. Literally. This is the way.

Not upto the mark.

Amazing product, however this listing is for the US version, which is 110V and UAE has 220V so this device will just overload and get damaged mine worked for 3 days before giving up, I did not notice the voltage rating sadly, Amazon was nice enough to refund me. Look for the UAE version or a 220V version of the same skimmer, it was amazing when it worked.

Excelente compra, lo recomiendo.

Great piece of kit and cleared the surface up in just minutes as I had seen it shown on YouTube.

Was soll man dazu groß schreiben, super Skimmer, hochwertig verarbeitet und leistet beste Arbeit in meinem 570 Liter Becken.