Loma Ponder Thank you for your thorough response. I have 5 koi that are 12-18 inches maybe a little larger. I also have 15-20 2 inch babies which are a product of last years goldfish breeding frenzy. I since gave them away but noticed yesterday that some of those "babies" are chasing another one around the pond. Can they breed already? I have been feeding my fish once a day for the last week or so as the temp of the pond has reached 80 degrees in the afternoon. before that, I fed them according to the pond temp and pretty much stayed with the wheat germ based food...Now, I feed them nishikoi high growth (43% protein) As for the UV I didn't look directly at the bulb. you can see a lavender reflection at night. I have a 70 ft. stream which was loaded with string algae and was dumping a bunch of stuff into my pond so I shut it off for a couple of days and just let the bead filter handle the pond. I cleaned the entire stream, and turned it back on... I have an aquascapes pond with a grande biofalls etc..which is why I purchased the additional filtration....No bottom drain but I did take all the rocks and gravel out of the deepest part in the middle of the pond which is approx 4 ft. deep. I also took all of the rocks out of the stream so it makes it easier to clean it...the pond has only a small amount of algae actually growing in it...the stream is the big problem . The water was changed in the fall and almost completely changed this spring with regular 10% water changes. I usually just put the bead filter through a rinse cycle once a week. I backwashed a couple of times only. I hope I'm not overfeeding...once a day for 5 or so minutes and they beg all day long for more. I enjoy feeding them but will cut back to see if this is part of my problem. Thanks again.

The UV Sterilizer-Clarifier at my pond is run June thru September or any months there is no freezing weather. These are the warmest months when algae grows the best. it doesn't cost that much to run. You will learn more after it has run for a while . Happy water gardening.

I'm no worried about pump size and flow....I'm fine with that. I was more looking for good or bad reviews on the manufactures. Bad experiences? Poor construction, ect. For what its worth, its a 1500 gph pump to the filter w/ 1" hose, but that can split it off and valved to reduce flow down through the UV filter.

The thing is, and this is from my understanding and research, if the UV filter says to use a 100-350 gph pump but you are using a 900 gph pump, the water might be flowing too quick for the filter, in particular past the UV light part of the filter. Apparently each drop of water needs to be in the light chamber for a certain time in order to be zapped by the UV light most efficiently. If it's flowing too quickly past the light the water might not get the exposure to the UV light that it needs to kill algae. Though I guess, in theory, even those each drop of water is exposed for a shorter than normal period, it might also be exposed to the uv light more times per hour with a more powerful pump. I guess too strong of a pump can cause problems with the efficiency of the filter and the inserts and gaskets, or might be hard on the pump too. Of course, just because a pump is rated 900 gph doesn't mean it's actually pumping 900 gph by the time the water reaches the filter intake. For every foot the water has to travel through the tubing/hose or every foot the water has to ride above the water, it causes drag. Still 900 gph pump with a 350 gph filter seems excessive. Glen