allpondsolutions 11w UV Light Steriliser for Pond & Aquarium - CUV-211 Fish Tank Pond Clarifier - Helps Remove Algae and Greenwater

I've had different shapes and sized ponds for 15 years now with a fairly high stock of fish and I've bought 3 of these over the years, they are a great product and last the distance, very easy to change UV bulbs which usually last a couple of years, only reason I had to buy a third one was because the garden flooded and submersed it and blew, that doesn't bother me as it does state that they are waterproof and are not submersible so remember to keep them off the ground. Always had them connected before my filters or before the bio media filter and I've had no algae or bacterial problems for years... It's great for ponds that use water pumps (Gravity fed drain systems are perfect but would still use these in my experience) as the tabulated system inside allows the water to stay in the UV chamber for longer without slowing down the water pressure allowing it to be exposed to the UV for longer to kill parasites and not just little bacteria or algae. With this style UV that has the tabulated system inside i would highly recommend it over just a clarifier. Considering it's a lot cheaper than the likes of an Evo clarifier and at a bigger wattage is a win win, nothing against Evo they are great products but these do the job perfectly for a lower price.

My garden fish-pond had a severe attack of "green-water" (mainly blanket weed growth) following the winter, and the water had become nearly opaque. After fitting this steriliser in front of, and in series with, the pond filter system, the water was virtually clear within a week. I can now see the fish clearly right down to more than a metre below the surface. A very effective device. It's advisable, of course, to choose a model that's capable of dealing with the particular pond size it's used for. The UV light has the effect of killing and coagulating the blanket weed spores and cells.

Easy to install, does what it says, good value

Great item and great price. The pond water is crystal clear now.Thanks

Care to replace works well needs care to fix

Every year I get a problem with a type of algae that grows over everything and so far can find little that touches it, but I also get a problem with single celled green algae that this year literally turned my koi pond into pea soup. I've tried numerous "chemical/biological" treatments and none have worked, these frequently have had mainly five star reviews saying how they have produced crystal clear water yet plainly these have been fake reviews since I've found just like all those who gave them one star that they were useless. So I started looking at UV as a solution and once again I was faced with numerous 5 star reviews stating how good it was and then one star ones saying how useless it was, although I have to say some of these negative reviews weren't necessarily regarding green algae. I was also rather sceptical since my pond filter has a built in UV lamp and that plainly wasn't sorting the issue. Further research showed that my in built lamp was to sterilise the water leaving the filter so obviously wasn't a green algae solution. I decided I needed an extra inline UV lamp before the filter and picked this one since it was close to my flow rate but allowed some wriggle room to make sure it wasn't trying to work on a wrong flow rate. Now this is where it's going to start sounding like a fake review but literally within 24 it really did look like the water was clearing, not a lot but definitely better. Within days it was obviously working and the water was looking clearer! We are now into the third week since I fitted it and the pond is almost clear of the green algae. Do not buy this for anything other than getting rid of green algae, it only has an impact on algae but unfortunately despite it being advertised as this use and this use only some buyers have bought it for brown or other types of water and then given it negative reviews for not working. I only wish I'd taken a before and after picture but I never imagined it would firstly work this quick or secondly work this well. So to repeat if you have a problem with green algae get one of these (make sure you get one suited to your pump) it really really does work!

Brilliant thanks

Purchased to replace previous 18 watt clarifier having looked for a price bracket i could afford. Had problems fitting the usual struggle with leaks and pipe clips that have a mind of their own. Ended up replacing corrugated pipe with newer more supple one as being outside for a long time they tend to become stiff and brittle .some of the clips on the market are poor and require a spanner to tighten. Finally mounted the unit on my shed next to the pond , another pain the ballast block attached to the cable means you can,t feed the the short cable through a hole in the shed to reach the electrics as with previous model. , so had to cut slot in door frame to allow access. Anyway attached plug and ran pump so water was running through unit as advised plugged in but no light showing in unit so gave up til next morning. Next day took out bulb and checked connection , turned out it was the clip in the bottom of the lamp holder , a small transparent clip which has to be pushed into the base of the bulb to lock it in place when you work out which side of the spring clips it goes in. Eureka!! we have light .. But for how long? the Ballast unit gets so hot i,m frightened it might fail and end up burning down the shed !!! Oh what fun.!!! One week on and the lamp is doing its job ok, have the " Pie Heater " resting on an old marble chopping block to diffuse some of the heat . Only time will tell how it goes on.. 1 year on new 18watt bulb still working but now can see band of light on body which shows up at night!! think this must be designed for people who use two outlets because they won,t have the sight glass. P. S. Some people buy uva lamps thinking it will kill Blanket Weed, it won,t you need a separate treatment for this. See attached photo to show you don,t need sight glass at night to show lamp is working.P.S. has failed after 2 years hole in body has appeared which was very thin , no wonder i could see the light through it !!! see pic. Jack Lumbered again.....