Hydor Koralia Nano Aquarium Circulation Pump, Includes Built-In Cable Protector, 240 GPH, Measures 2.4-Inches & is Ideal for Fresh or Salt Water Use

Great product and pump. Has a lot of strength and water flow is wonderful when you use it. Most of all its quiet and you don't hear it. I wish this company made a wavemaker. The size isnt too small for a nano tank making it easy to position. The larger sizes do tend to jump quite a bit in size and weight.

The media could not be loaded. (Noise in video is from fan inside tank light, not wave maker) I purchased the 240 GPH one to create surface agitation to replace my air stone, and to create more of a shimmer effect in my tank. I was worried it might make too much current but it doesn't, and it is 100% silent! When I first plugged it in, it sounded awful, but after just a few seconds it became completely noiseless. My tank is directly bedside my bed and my filter is silent as well, so if this thing made any sound I would hear it.Another bonus is that the magnet attachment makes it super easy to move around, and I don't have to worry about it ever falling.

Great pump, especially for the price. I put this into my 30 gallon bow front. It provides great movement and is silent.

Thanks to the reviews, I decided to give this pump a try for my 9 gallon Eheim Aquastyle saltwater nano. I've been in the hobby over 10 years - mostly heavily planted, aquascaped freshwater tanks in the past from 50g to 0.5g. I've always been very pleased with the Hydor products and this one is no exception. For the quality, price and function, this is a great pump, especially on Amazon. I wouldn't go cheaper with a more inferior brand or even a more costly one that does the same thing.I found other reviews with tank descriptions especially helpful so here's mine: my saltwater nano has 1 clownfish, 1 cleaner shrimp, cuc's and several soft corals of starburst polyps, kenya tree, pulsing xenia and mushrooms - live rock and 1 inch live sand (sand is more aesthetics). Eheim's tanks are beautiful on their own, so every accessory counts going in. Most importantly, I didn't want the other inhabitants blown in a circle or with such force that they would have to hide in a corner of rock. Sure enough, based on the reviews and other research on fish boards, the open flow of this pump is gentle enough in the tank for everyone. Based on my live rock formation, I have the pump on the back left side, a little lower than mid-tank directing current toward the opposite wall with the corner filter (sand gets kicked up if placed lower). The pump creates a soft current that wraps nicely around the rocks to give the corals a gentle sweeping effect in combo with the filter flow overhead. The starburst polyps have already grown larger in the past week and the CUC's are out and about more often in the light. Another benefit is that the sand has been cleaner too, even as I increased my light hours for better tank viewing in winter.Since I have only had the pump 2 weeks, I am giving it 4 out of 5 stars. As other reviewers mentioned, there is a slight hum to my otherwise nearly silent tank. But the animals all seem more lively and "happier" with the added flow so I'm keeping it. If the vibration gets much louder or circulation fades, I'll likely replace it with another one. Hopefully the sound remains minimal and pump lasts a couple years. If so, I would vote 5 of 5. Cheers and happy reef/fish keeping!

I didnt see the need for this in our aquarium. Hubby got it and so I put it in. I’m glad to say I was wrong! Our tank has been healthier and our fish seem to love it. It helps feed our bamboo shrimp too. He is frequently perched wither in front of the powerhead or by the intake. It also helps super oxygenate the water as some of the bubbles get sucked up then pulverized into tiny bubbles and strewn across the tank. I like it so much that this is the second one we’ve purchased. The first one eventually quit on us.

Ever since I got this, my fish of two years started turning up dead and stuck to the power head. One tetra on a Monday, two pencil fish on a Thursday, and so on. They had no sign of illness or wounds, and the day before swimming and eating like normal. I thought maybe there was something wrong with the fish, but they looked healthy and were active, and I've had the tetras and corys (which one died as weel) for two years, and the pencil fish for 6 months.Today I found one of my bettas dead with red swelling on her tail. This betta liked to rest underneath the power head. I looked up death from power heads and learned electrocution is far too common. I removed the power head and found some of the betta's skin/scales stuck to the cord where it connects to the power head.The flow is also bad. It started out fine for the first week, but got slower until it was barely any better than my hang on back filter.The risk of electrocution and the fact the flow is no better than a hang on back filter makes this a dangerous product.I also want to add I did not intend to buy this. I was just looking at power heads on the amazon app, and the app is bugy and freezes a lot, and when scrolling down, the one-click purchase ended up being clicked during a freeze. I canceled the order within minutes of it happening, got the email confirming it was canceled and the money refunded. Yet a few days later the power head was still shipped and I was charged. I decided to try it out anyway instead of going through the hassle of returning. I should have just returned it.Don't risk your fish with this.