OASE CrystalSkim 350 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 92 Gal / 350 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.

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.

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.

It is not something you plug in and solved everything. You need to 1. Adjust the placement with the water level and when it is right, you will see the oily film running toward it. 2. Clean the filter regularly to continue working. 3. It can also be used to remove the duck weeds and surface trash. 4. For a 75 gallon, only one side will be able to cover, so you need to move to another side to clean the other side. It will not work for lazy people.

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.

Not upto the mark.

Was good at what it does. But stopped working with 40 days even though was using 1 day a week. Disappointed

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.