Grech CBG-800 5W UV Sterilizer Hang-On Back Filter, 20-50 gallon/211 GPH, Black

The UV feature is amazing when setting up a new tank or if you get an algae bloom. I set up a 10 gallon tank for some guppies and platies and within a week the water clouded up due to an algae bloom (typical for a new tank). I turned on the UV light and within days it was crystal clear. Once it cleared up, I turned off the UV lamp and the water has stayed perfect. I also like the filter design. You don't need to purchase expensive same-brand cassettes/filters or anything. You can use your own media and build up the filter however you like. I'm using ceramic bio rings, crushed coral in a mesh bag, and the foam that came with it. The water is crystal clear and all water parameters are exactly where I want them. Lastly, but not the least important thing I love about this filter is that it re-primes itself after a power outage! I have tried several other small HOBs that couldn't and they burned themselves out due to lack of water at the impeller. As long as this filter stays in the tank and water levels are where they should be, it has restarted EVERY SINGLE TIME we've had a power outage. One outage was 4 hours long and this was humming along when I got home. Other notables: - it's quiet - easy to set up - easy to clean - flow is adjustable - it has a surface skimmer that is adjustable and works great

I've had an odd 37gal square-ish tank for 5 years now, and it's always been a struggle with algae and clean water without breaking the bank on expensive disposable filter cartridges. A complicating factor for mine is that there is an aquaponics bed on top and it's in a corner making room above and around the tank very limited. I've had this for about 6 weeks now, I've done cleaning on it 3 times in that time (there was a LOT of algae initially), but now that it's under control it's going longer between cleanings with no problems. What I absolutely love about it: -Minimal consumables. Occasionally you can change the filter floss on top, and every so often toss out the carbon and dump some more in. But the boxes make it so you don't even need bags for the carbon, and it's a tiny rectangle of filter: perfect for buying bulk material to save money. -Easy to clean: The first time it took me 20 or 30 minutes, but now that I'm practiced it's a 5-10 min chore at most. -UV Sterilizer: the UV sterilizer is a nice touch, and I don't know if it's intentional or not, but when the filter is clean, and the tank is not generating a lot of solid waste, it only flows a small amount of water through it. If the filter plugs up, more water gets sterilized. Almost like it's self-adjusting. -Noise: it's very quiet, as long as the water level is above the skimmer. When the water level falls below the skimmer, it starts skimming air (go figure) and it makes a quite annoying sound. I wish it didn't, but it motivates me to add water. -Pickup tube: it comes with an extension tube that makes it able to reach deeper in the tank than any other filter I've ever had.

I like this pump and have two of them in my 26 gal tank (overkill, yes). What I've learned, though, is that the UV may/will help if your water is cloudy. My water has always been clear, but I've instead had algae growing on surfaces in the tank. A couple of bristle nose plecos has fixed that much. But to me there is a significant issue with the skimmers. Everything worked fine for several months until the skimmers on both pumps simultaneously began oscillating up and down, causing the pump to cavitate and unprime itself. It was very, very noisy and I'm sure the pumps were running at reduced efficiency. The fix, finally, was to pull out the skimmers and stuff in cork stoppers from some bottles of port (wine corks are surely fine if they fit). Instantly, the pumps were super quiet and functioning at full efficiency. I'm not sure that the skimmers ever did much in my tank except to suck down a couple of my smallest fish. That won't happen anymore, either.

Terrible filter, first thing the skimmer is awful decision with no turn off, killed one of my snails. Second it didn’t run more than 2 weeks, check all parts and no issues with it. Just wouldn’t run no matter what I did. Just a trickle of water. No No do not buy!!!!!! Rate at a minus

I've never heard of the Grech brand in aqaurium filters before but this unit really impresses me. I've used a lot of small HOB filters and this one seems to be the best of all the major brands. It has a strong powerful motor for its size and creates a nice current at its output. I use this filter on my 15G vertical tank. Its a perfect fit in size. Its loaded with all the features you could want: 1. NO, yes NO proprietary removable filters! Saves on $$$. 2. Uses a sponge filter and 2 filter boxes you can load with chemical and biological filtration media of your choice. Comes with both an activated charcoal filter bag as well as ceramic media balls. But you can choose your favorite media to use since they just fit into individual boxes. 3. Provides for mechanical/chemical/biological filtration for maximum water clarity. 4. Also includes a surface skimmer to suck up any oil/whatnot slick that may form on the water surface from food/chemicals you may use 5. Includes a 5W UV filter to kill parasites and algae that can infect and cloud the tank water! This is a big plus! 6. The unit is heavy and substantial in build with a strong motor for high water flow in small tanks. 7. Water flow and surface skimmer are fully adjustable and the UV lamp can be manually turned on/off as needed. 8. The entire filter mediums are in an easily removable (use 2 fingers) stack for cleaning and replacement without shutting the unit off or making a mess. Pretty much everything you want in a small HOB filter is here and seems to work very well. Overall, highly recommended. Finally the seller provided very fast shipping on this item. It came at least 4 days sooner than expected and in great condition!

I was a bit skeptical when I ordered this but I have a problem 40g tank and needed either more or better filtration. As much as I'd like to, I can't put a canister on this setup unless I want to tear it apart and move it. not gonna happen anytime soon. I liked that this hob has both the protein skimmer and uv sterilizer. And that the input flow for both the skimmer and the intake are adjustable individually. Seems like all stock media with any filter is low quality, no surprise. I did keep the sponge, loaded both trays with the media of my choice, fitted it all together, dropped it in and fired it up. ... Its been on the tank about two weeks now and I'm impressed so far. Its not the quietest, but quieter than others. The uv light is working great. Ive been running the light off and on for about 12 hours at a time over the last 2 weeks, and the bright green algae spots have almost all disappeared. The water is the clearest its ever been in this tank. The protein skimmer can be a bit noisey, but once you find the right flow adjustment it doesn't seem to be a problem. But, the true test is yet to come. I do still have the previous hob running , its the one that didn't seem to be doing its job well. I figured a month with both running to get the bacteria in the new filter, then I will remove the original hob and see how this one does by itself. I'll try to remember to come back and update my review, too.

Well, I have to say that this is a great filter. Once it is started and fine tuned it is very quiet for a hang on the back-style filter and the media organization is excellent (and perhaps superior to Aquaclear filters. HOWEVER- this was not an easy filter to set up. It would not prime no matter how much water I poured into it. And it was sucking in extreme amounts of air causing a ton of noise initially. I looked for troubleshooting help in the manual which was useless. Fortunately, some helpful Amazon reviewers made som mention of trying to make sure that the knobs for adjusting the surface skimmer and intake were fully seated. When I pressed on them the filter suddenly started operating, however it was still noisy. When I stopped pressing on them the filter list it’s prime. After this, I decided to remove the knobs and see what was going on and I found badly seated and damaged o-rings. I thought that this must be the problem, so I went to my parts bins, found some O-rings that were close enough to the originals and replaced them as well as coating them in a very small amount of food grade silicone lubricant. Suddenly, the filter operated wonderfully. It had great flow adjustment and even with the skimmer, it was nearly silent. It’s now operating perfectly and this is perhaps one of the best HOB filters on the market. I would have rated it at 5 stars if I didn’t need to do so much troubleshooting and replace o-rings before ever getting it running. There’s definitely a quality control issue at the factory. However, once it’s running, this is a phenomenal filter.

Love these filters, I wish more Aquatic filter companies made 4 in 1 Filters like these.

This filter started going very hot and smelly within 3 mins of running to check that it had started to melt and smoke. do not buy this EVER

Llevo 4 días con el filtro, y ya se notan los resultados. El alga verde no podía quitarla por mas intentos que hice y cambios en la pecera, tales como bajar cantidad de peces, agregar menos alimento, tapar la pecera completamente por 3 días, hacer cambios frecuentes de agua, comprarle un fiultro extra. Bueno, ya estaba desesperado y ví en varios videos de youtube que la solución mas eficaz era luz UV, y así lo hice. Ya van 4 días y los cambios en el agua son notorios. El filtro es muy silencioso, trae varios niveles para poner esponja, canutillos (filtro biológico) y carbón activado. Un filtro muy completo y su relación calidad precio es inmejorable (a mi me salió en $843.00 la compra mientras que en Mercado Libre estaba en $1,650.00 el mismo filtro - y eso que estaba barato en ML). Hoy, ya tengo 9 días que instalé el filtro y encendí la luz UV, y finálmente se acabó el problema del agua verde (algas unicelulares). Contento con mi compra y me salié a un excelente precio.

Actualización marzo 2024 El filtro sigue funcionando, sigue dandole a mi pecera la claridad y calidad del agua, lo único es que se está desgastando la esponja, con un cambio de este componente estaría como nuevo. No me arrepiento de hacerlo adquirido y lo volvería a comprar, es un producto eficaz y comprobado en mi experiencia como acuarista profesional. Actualización**** octubre 2023 ***** Después de casi un año de uso, diria que es mucho mejor que cualquier filtro del mercado, deja el agua super cristalina y realmente funciona a la perfección. Casi nada de ruido o nulo ruido. Excelente filtro para un acuario de 100 litros, buena circulación y excelente luz uv que ayuda a que el agua no era ponga verde. Mantiene el agua cristalina. Es realmente silencio, no se nota el ruido a menos que pegues el oído al motor La luz UV es algo muy bueno si presentas algas en el acuario. Muy buena distribución del material químico, biológico y mecánico. Lo probé en mi acuario de 100Litros. Todo ok. Iré actualizando. 15 dic 2022 ** Actualización 15 jun 2023 Es el mejor filtro de cascada por las prestaciones que ofrece, sigue funcionando sin ningún problema y sigue igual que el primer día que lo compre. Sin duda es un filtro de cascada excelente. Me encanta. ***Actualización*** Después de 2 meses de uso puedo decir que es bastante bueno, mi agua está cristalina y no utilizo ningún producto para adicional. Mantiene excelente mi acuario Aparte ya me di cuenta que no se vacía cuando se va la luz, el truco está en llenar tu pereca hasta el borde inferior del plástico de la cascada.

OK GOOD

Never worked