We have 30+ years experience in the pond industry.

“Help! My UV Sterilizer Bulbs Keep Burning Out!”

image004This tale of pond triumph comes to us from Kevin, one of our esteemed technicians, and it highlights some key concepts that we try and emphasize to our clients:

  • Bigger is not always better. A pond is a living, growing ecosystem, and so when we help our clients choose filtration equipment we always stress the importance of having a certain margin of error in your pond’s filtration capacity: as your fish grow and multiply, you want a system that can grow with them. Likewise, if your fish happen to become overfed or if a fish dies, you need your system to be able to handle the extra load. But this does not mean you should simply buy the highest-capacity filters and sterilizers you can afford.
  • Read the manual. A piece of equipment that is installed incorrectly might work fine for a while, but over time, the stresses of continuous operation can turn a small mistake into rather an expensive mess.


A new client has a 3,000-gallon pond with 11 large koi. To keep his water clean and clear, and his koi happy and healthy, our client told whomever installed the pond originally that he would spare no expense, so this is what he ended up buying:

  • Aqua-Ulraviolet brand 200-watt SL ultraviolet-light sterilizer (pictured above)
  • Aqua-Ultraviolet Ultima II 6000 bio-mechanical filter unit
  • Artesian PerformancePro high-efficiency low-rpm water pump

After installing and running all of that top-quality gear the pond looked great… for about eight months. Then the UV sterilizer burnt out its bulb. Eight months later, another bulb. What seemed like a great investment at first was now turning into an expensive problem.

There are a couple of factors at work here:

  • The client’s UV sterilizer is totally oversized for the amount of flow being generated by his water system. A unit this size has one high-intensity UV bulb, and is designed to accommodate the highest of flow rates, up to 9,200 gallons per hour, on ponds between 9,000 and 30,000 gallons. It has inlet/outlet ports that are 3” in diameter. Basically, this thing is a beast. However, the client’s pond is nowhere near that size, and while his pump technically is capable of generating enough flow, the UV unit is plumbed with pipe that is only 2” in diameter. The unit simply cannot get enough water flow. So the client paid extra for more capacity, which means he continues to pay extra on his electricity bill, but a lot of it is going to waste.
  • On top of that, as eagle-eyed readers no doubt already spotted in the above photo, the client’s original installer installed the darn thing upside-down. So air would get caught in the unit, and because of the lack of water flow, nothing was pushing the air out. The high-intensity UV bulb inside the unit generates a considerable amount of heat, and when the unit is working properly, the constant flow of water around the bulb keeps it nice and cool. But with all of that trapped air, the heat gets trapped as well, causing the unit to burn through bulbs after only a few months. Those things are not cheap.

But that’s enough bummer-talk, because it’s time for the happy ending:


Kevin swapped out the UV sterilizer with an appropriate-sized unit from the same manufacturer. The new unit only draws 80 watts to power two smaller bulbs, and takes full advantage of the client’s plumbing system. And here’s the best part: the entire replacement unit costs less than just one replacement bulb for the old unit. And now, as with all healthy and thriving ponds, the results speak for themselves:


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Los Angeles based L.A. Pond.com is one of the largest and most established distributors of pond and water garden products in North America. For over 30+ years they have supplied hobbyist, pond professionals, and commercial parks with the best fish, aquatic plants, filters, pumps, and more.

Other sites just sell products - L.A. Pond.com researches, tests, and uses them with proven results. All products for sale through their distribution network are used by L.A. Pond.com maintenance professionals in the field on a regular basis.»


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