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Pondmaster Ultraviolet Light Pond Water Clarifier Series

Pondmaster Ultraviolet Light Pond Water Clarifier SeriesDescription

Has your backyard pond been given you trouble with severe algae? Maybe you did a water change and cleaned it out, only to find out the next day that it was green again? It’s hard to enjoy your fish with a pond in a state like that.

This UV light is very effective at curing your pond from the green pond syndrome. Water is pumped through the UV light and kills the suspended algae. The dead algae can then be trapped and gotten rid of.

This UV light can be installed outside of the pond, or submersed in the pond.

These clarifiers have a 3/4 barbed inlet and outlet and it comes with an 18 ft power cord. The color is black and thus unobtrusive, whether in or out the pond. The soft blue halo light rings show that the unit is working. The vortex flow design increases the exposure time of the algae to the ultraviolet light, and the slim diameter makes the process more efficient by bringing more of the water closer to the intense UV rays.

Requires appropriately sized and tubing.

All models come with a 1-year warranty.

UL listed.

Also included:

  • 9000-hour 20-watt lamp
  • transformer
  • 18-foot power cord
  • watertight quartz sleeve

There are 3 models in this series: 10 W, 20 W and 40 W.

Let’s list them here and then have a look at the pros and cons of this series.


Pondmaster UV Pond Water Clarifier 10 Watt

Pondmaster 10

As a clarifier, this model is designed to work with a pump of up to 700 gallons per hour flow rate.
As a sterilizer, the max gph is 250 gallons.


Volume of pond served: Use in ponds of up to 1,500 gallons.
Product Dimensions:1258 x 3¼ inches
Shipping Weight: 4 pounds
3/4″ Barbed intake and outlet
1 Halo ring to see whether the light is working

Click here to see this product on amazon


Pondmaster UV Pond Water Clarifier 20 Watt

Pondmaster + bulb + sleeve


Use with pumps with up to 1,800 gallons per hour of output.

Volume of pond served

Clarifies water in ponds holding up to 3,000 gallons.

Product Dimensions: 18½ x 3¼ inches
Weight: 4.4 pounds
Shipping Weight: 4.6 pounds

1″ Barbed intake and outlet
2 Halo rings to see whether the light is working

Sorry, as of now this product is discontinued by the manufacturer.



Pondmaster UV Pond Water Clarifier 40 Watt

Pondmaster 40 W large


Pondmaster 40 + bulb +sleeve

For use with pumps up to 3000 GPH

Volume of pond served: In ponds up to 6000 gallons

Product Dimensions:24 x 3¼ inches
Shipping Weight: 5 pounds
Intake and outlet: 1 1/2″ Threaded w 1 1/2″ Barbed Elbow
3 Halo rings to see whether the light is working

See on Amazon here


About PondMaster

Danner Manufacturing (the company that makes these filters) has been around for over 75 years. In 1934 they started modestly as a family owned and operated business, developing and producing pumps for hobbyists and professionals.

The products they manufacture now are focused on Water Gardening, Aquarium, Pool & Spa, OEM and Hydroponic industries throughout North America and the offshore markets. We are committed to offer our customers high quality and reasonably priced products, creating the best values.




This video shows you, after a general introduction about Ultraviolet lights in ponds, the PondMaster 20 W unit up close:



The Pondmaster series is for sale on Amazon.com, and after having a look at the reviews there from people who bought the product, there are some pros and cons that have become clear.


There aren’t many in-line clarifiers on the market that are submersible, but this is one of them. So, if you prefer to easily hide your clarifier, then this in-pond model might be what you’re looking for.

Also, the build quality is excellent and nobody has mentioned any problems with leakage of water, either into the interior quartz sleeve and UV tube or out onto the floor (if it is situated outside of the pond).

The general agreement is that this UV light works very well. It is simple to hook up and use, and is also very effective. People say that it cleaned up their pond water even faster than they expected. Here’s a reaction of an actual customer:

“Our neighbors that have fish ponds are still cleaning their foam/mesh filters at least once a day, and their ponds are still green. I’m cleaning my pad filter once every three to four days now and our pond is crystal clear.

Very impressive that something this simple would work so well. I would highly recommend this pondmaster UV water filter to anyone.”

Another benefit that people mention is the halo glowing ring, which is very helpful to let you know the light it’s working.


About PondMaster customer support

Another pro is that customer support from PondMaster is very helpful. People who have contacted them have successfully done so and have been helped out. This is a customer who received a PondMaster 40 W that wasn’t working for some unknown reason:

“The next day I contacted Pondmaster to complain, but they quickly began to resolve my problem. They sent out a new ballast which arrived in a few days and a complimentary bulb. The new ballast works fine. They made this process extremely easy for me and they didn’t need to. This was an example of how a company can turn a bad situation into a favorable one because after this experience I wouldn’t think twice about purchasing another Pondmaster product.”


On the whole people are very happy after purchasing this product. The price might also have something to do with that. On top of the positive qualities mentioned, every unit in this series is reasonably priced as well.

Click here to see prices on amazon:

The Pondmaster 10 watt clarifier
The Pondmaster 40 watt clarifier

(The Pondmaster 20 watt is discontinued)



Even though most people are happy with the quality and effectiveness of the Pondmaster series, some people have had some issues with this product.

For example, some have mentioned difficulties installing the system. There are instructions that come with the light, and these tell you how to assemble the UV light (click here to see the instructions). But this manual doesn’t say anything about the placement relative to the pump or filter. There’s no diagram. Some people who do not feel so confident are deterred by this.

There is probably no diagram or such because there’s really not much to say about it. About the only thing that could be said is: “Connect the outlet of your filter and the inlet of the UV light with a flexible tube. Then put a tube over the UV light outlet, and this tube goes back to the pond.”

But even so, how hard was it to include a diagram in the instructions?

On top of that, in the manual, the barbed intake and outlet sizes for the 20 watt model are different than what is mentioned on their website. On that site it says:

” 1 Inch Barbed Fitting for Inlet and Outlet”

While in the manual (link) it says that both the 10 W and 20 W model have 3/4 inch barbed fittings.

That’s why people have said about this UV light:

“It is easy to install if you have the right size tubing.”


So, most probably because of these confusing details, some people decided to return the UV light:

“…therefore I returned it. Returning it and getting refunded was not a problem.”


Others were more proactive and have called or mailed the manufacturer for instructions, and after that everything went well:

“Once item arrived I had to call manufacturer for instructions for use. Item included assembly directions but none how to hook up to pump/filter. But once in place I could see a difference within 24 hours and within 5 days my pond was clear! Good product just needs better instructions.”


Others just trusted their diy-skills. When people are having this issue, it seems to come down to inexperience or being ‘not-so-handy’. But if you feel confident or have someone who can help you out for a bit, then you should have no problems. In fact, this UV light is no different than other UV light when it comes to installing, so this whole matter is probably a bit exaggerated. It’s actually really simple. Some people have no trouble whatsoever:

Unlike some reviewers, I had absolutely no problem hooking it up to my Pondmaster filter and pump with standard 1″ tubing.


Another thing to be aware of

Don’t underestimate your needs.

The 10-watt model should be adequate for ponds up to 1500 gallons. Some people experienced this to be very optimistic. If you begin with a pond that is absolutely clean and algae free, the 10-watt model might keep it that way (if you use a good filter along with it).

However, if you are installing the clarifier to deal with a pre-existing problem, you should probably not count on it working well for ponds over 500 gallons. Someone has mentioned their 650 gallon pond, and the 10-watt device was barely adequate.

Granted, this might have a lot to do with the specific situation of the pond. Is it in full sun? Are there few plants and a whole load of fish? If that’s the case, algae will be likely to grow more abundantly. A stronger UV light will be required then.

There is relatively little difference in the cost of the next-up stronger model, so why not go for that. Using more UV than you need doesn’t harm anything (it’ll only make it more effective) and at most adds a few pennies to your electricity bill.

Excellent product but it’s easy to underestimate your needs. So, if in doubt, ALWAYS go for the stronger model.



While this is not a con for this model specifically, it is important to remember that you will need to clean the sleeve of the clarifier periodically, just like with any UV light. This quartz sleeve will gradually become dirtier because of deposits on its surface. For best results it is really recommended to remove and clean the sleeve now and then. You can use vinegar and a scrub pad for this. Disassembly is quick and easy, but be careful with both the sleeve and the bulb itself. They are the more fragile parts of a UV light.


Any guarantees?

As with most products, this UV light too comes with a warranty. All models come with a 1-year warranty to ensure you have a unit that is working as it should.

People who wanted to return their PondMaster unit for any reason have done so without any problems.

Somebody said about this:

“…too small for my use. I returned it with no problems and got one bigger.”

And someone else:

“I first bought a smaller size and was able to return it with no hassle. Got the bigger one and it works great.”



Looking at the reviews people made about this product, this UV light is definitely of a good quality. Some minor issues exist with instructions on how and where to connect it to, but this is really straightforward and should be no obstacle to using this UV light. It is not more or less difficult than any other UV pond clarifier or sterilizer.

A product definitely worth having a look at:

The Pondmaster 10 watt clarifier:
see the current price on amazon here

The Pondmaster 40 watt clarifier:
see the current price on amazon here

(As we said, the Pondmaster 20 watt clarifier is discontinued by the manufacturer now.)


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