Please visit our Sponsors

FAQs on UVs in Pond Filtration

Related Articles: Ultraviolet Filtration for Ponds, Pond Filter Media, In-Pond Filtration, Up-flow Filtration, Pond Filtration, Biological Pond Filtration,

Related FAQs:

Aquatic Gardens

Ponds, Streams, Waterfalls & Fountains:
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples

V. 1 Print and eBook on Amazon
V. 2 Print and eBook on Amazon

by Robert (Bob) Fenner

Help for my Laguna filter      1/7/17
Dear Crew,
I have a 700 gallon stock tank for a few red eared sliders. I have the Laguna Pressure Flo 4000 filter and a Cal Pump T1200.
<Mmmm; yes... for all, here is the pertinent Users Manual:
See towards the end of page 3 and page 4>
I can't close the locking band around the top of my filter without help from a strong person. The top is hard to push down. Is there a trick or some other solution?
<There may be a few things working against you here. The most common are that the seat area on the filter body isn't absolutely clean, the second, "Before applying the lid clamp (O), the lid (G) must be pressed down until the gap between lid and filter case is eliminated. The lid clamp must be latched, with the safety metal lock (Z) inserted correctly inside the latch slot (Fig. 3). "
the last is that the filter body o-ring isn't clean and well lubricated (swimming pool/spa Silicone is best here)>
Also, do I need the UV light?

<It does help with improving water quality, particularly in reducing free-living (floating) algae>
If it just kills the bacteria I've added, can I just not replace it when it burns out?
<It should be replaced per the manufacturer per the number of hours service it has run. The UV lamp will "burn" (show light) when it is beyond its effective life.>
Thank you,
*Lou Anne*
<Welcome. Bob Fenner>

18' round Koi pond that gets full sun from 10 a.m. until sunset during the summer months in Boston, MA. Alg. f'    8/15/11
fyi: I have 10 good size Koi fish that range in length from 10 to 20 inches.
They've had babies. I caught a glimpse of a 1" baby a couple of days ago, a 2" in the spring/early summer, and two 5" that I think were there last year but the water was so dirty I couldn't see them.
It's been 3 years since I installed my Koi pond. I finally can see the bottom which is 38 " deep in the center now that I've installed a 4' UV sterilizer (last year it was a bio filter /UV). The company that sold me the UV sterilizer said it wouldn't hurt the good algae because it attaches itself to the bottom and sides of the pond. I called the manufacturer and they also said it doesn't kill the good algae. They both said it doesn't need to be in-line to the filter (wrong! it was spewing dead algae back into the pool, my filter couldn't keep up with it and I believe it was the cause a low level Nitrite reading. Now that it's in-line life is good and my fish are acting happy, I'm backwashing daily and getting out a lot of brown gunk.
<I see>
I've read so many articles I don't know if I have the good algae or not (translates into I don't know who to believe anymore). Do you have an opinion?
<Define "good algae"... the UV will kill a good deal of "water borne" micro-organisms...>
Should I add some good bacteria on a regular basis?
<IF your filter is large enough, the media employed suitable, you should not have to add bacteria>
To reduce the huge amount of free floating green algae, I'm thinking of adding die <dye>; three parts black and one part blue to reflect the sunlight which is supposed to reduce the algae growth. Will this have any
impact on the effectiveness of the UV sterilizer?
<It will not>
(I did search with an 'and +) and looked at several sites that sold them but I couldn't find any info on this combo.
You have an awesome web sight! I was never that good at Googling, you've taught me a lot of neat
techniques! Too all of you who share yourselves and your valuable insights, a very sincere thank you!
Warm regards, Gayle
<Please do review my articles on pond filtration, pond algae control and foods/feeding posted on WWM... You may well benefit from attaching a "plant filter" to your overall system here; as well as covering/shading a good percentage of the surface>
p.s. I'm a QA system's tester and I'd be happy to volunteer some time each month or once in a while (when it's not a release month at work). I work for ING and if I volunteer 50 hours a year they'll send you (I think you only have to provide your non profit number) $500.00.
<Thank you for this/your offer. Bob Fenner>
Re: 18' round Koi pond that gets full sun from 10 a.m. until sunset during the summer months in Boston, MA.   8/15/11

Thank you very much for your advice and time. I'm sure I'll learn a thing or two from those articles.
If you ever need a free QA... feel free to call me at XXXX
<Mmm, don't do calls. B>
Sincerely, Gayle
Re: 18' round Koi pond that gets full sun from 10 a.m. until sunset during the summer months in Boston, MA.   8/15/11
Hi again.
I just noticed the spelling correction <dye> (most days I'd get it right)
I'm sure you were being nice and letting the first <KOI> slip by. This new medication is making me spacey. Some QA huh?
I'm sorry! Have a great day
<Did correct early this AM. Cheers, B>

Pond Skimmer... and more re pond UVs, construction  12/29/09
Good morning,
I'm planning to remodel a small concrete Koi pond this spring. This will be the second time around and hopefully I'll correct the mistakes I made the first time.
<Heeee! Been there, done this a few times/iterations>
The original pond had a leaking plastic liner and a water channel near the top that led to a Rubbermaid trash can into which a Rio Hyperflow pump was immersed. The output of the pump went into an Aqua UV filter and from there into another round plastic tub that had filter media cut into discs. The water just fell through and drained out a pipe screwed into the side that drained into a waterfall.
<Make shift... but all the elements there>
I dug the pond out and lined it with concrete and then used Nelsonite Pool-poxy paint.
<Ughhh! I wish I had all the money I spent on Nelson's products... that didn't work. I hope your job is holding>
I cemented a regular pool-size skimmer into the side of the pond, then to a Sta-Rite 1/8 Hp self priming pump.
<Good, inexpensive (to purchase) brand... I'd look around for better energy-efficient wise. See WWM... the Pond Section/Subweb>
From there to a Laguna Chamber filter which has the baskets for media and bioballs and then MOST of the water flows out to the waterfall but with a smaller pump inside pumping about 25% of the water through the UV filter and then back to the pond. The idea was that it the water I wanted more "dwell time" in the UV. Everything works the way I intended but it's not quite "right" either.
We're digging the pond a bit wider and quite deeper, so I'm going to use a ployurea coating over the concrete rather than epoxy paint.
<Better, but still...>
I want to
add a vortex-type settlement filter before the media filter and put the UV filter back in the main line. Should it be before the settlement chamber, between that and the media baskets or leave it as is, at the end, exposing a small amount of water for a longer time?
<I'd leave as is. The move and consequent restriction in water flow is a bad trade-off>
Last, and this is the most up in the air, I'm rethinking the wisdom of having used a pool-type skimmer.
<Do keep the front screened if you leave in place/use... troubles with fish getting in/stuck...>
The size of the leaf basket is small, the diameter of the plumbing is restrictive and thus requires the self-priming pool-style pump.
<And inefficiency>
Given the energy efficiency of today's small pond pumps, I could get substantially more flow for quite a bit less wattage from one or more submersible pumps just sitting in the bottom of a secondary cavity fed from the top of the main pond.
Your comments and suggestions please?
<I would NOT use a submersible pump unless absolutely necessary... Please read here:
and the linked files above. Bob Fenner>

Koi pond question, U.V. lamp replacement  04/05/09
HI all
I have a 850 gallon pond i purchased a U.V. light two years ago, i have about (45) fish. my question is should i go threw my biological filter first and then the u.v. light. The reason i am asking this after two years is that
the water does not get is clear as i would like. Any idea why.
Thanks Ron Stanton
<Mmm, these lamps are likely shot... need to be replaced about every year if in continuous operation... Doesn't matter if they still "light up"...
they're not producing the wavelength of ionizing radiation you're seeking... I should also make a mention of being careful re the removal and the need to clean the sleeves, and... Bob Fenner>

Pond uv filter   3/23/09
I have a 150 gallon pond. I am looking for a new uv filter for it (canister type). The one I have is complete crap. And I see there are millions of different brands. Do you have any preferred brands for a pond this size? Please help.
Thank you very much.
<Ah, yes... I do... TMC's Vecton line is superlative... Are you in the U.S.? Have your dealer contact their distributor, Quality Marine in Los Angeles if so. Bob Fenner>

Green water, pond... UV use 6/17/08 Hello again, I have another concern. The water on our pond is greenish in color, we tested the water and everything seem to be fine. It is a fairly new pond, and we have been running it for about 2 weeks now. Do you think we'll be able to see the bottom even if it is 4 feet deep? Our filter is an Ultima model (bead filter) which I am sure is sufficient for my set up. I am wondering if maybe it is the UV that needs to be replaced/addressed? <Green water is often a good sign that the UV tube in a UV steriliser needs replacing. Do bear in mind the tubes in these devices lasts around 12 months depending on the model (check the instruction manual that came with yours for the precise details). UV tubes aren't expensive, and changing them is usually a 10 minute job, if that. Cheers, Neale.>

UV filtration needed (for large natural pond)? 7/16/05 Hi there.  We just dug a pond, approx. 35 X 60 feet, 8 feet deep max, with one corner to be a wetland.  We are  beginning to plant it with local vegetation today.  The pond is not lined, but has had rubble (3 to 4 inch diameter) added inside to stabilize the banks. <... and percolation? Oh, see you've addressed this below> There is a small sandy beach.  Dug the test hole last year and it holds water.  The pond is actually dug along the path of a natural drainage channel, at the base of a 20 ft rock wall.  (pics to follow)  Anyway, we have raised the natural water level about 2 feet.  Approx 50% Clay soils, so retention will be OK.  However, the source of the added water is a stream.  I know Coliform and other critters are naturally occurring in any surface water system. <Yes> The stream is thick with aquatic vegetation, a sure sign of nutrients I would imagine.  We are drawing water from further upstream to get the cleanest water possible.  But once it hits the pond, it's wide open, sunny,  and I would imagine bacterial growth will take off. A few questions: 1)  Should we use UV filtering.  Won't this kill all bacteria including beneficials? <Mmm, I would not use ultraviolet here... but would definitely look into ozonation directly> 2)  How much area should be wetland or vegetation? <At least ten percent> 3)  How do I stabilize the sandy beach which right now is like quicksand? <Mmm, depends on composition... would have a soils engineer, firm... depending on the make-up, you may be able to just add a bit of silicate, carbonaceous material to make this area more "solid"... at the very worst, a berm might need to be emplaced and the area back-filled with a suitable substrate> We will be running two waterfalls, one a height of 20 ft. <Wowzah! Do be careful re pump selection, operational cost here> and the other just a 2 foot rise over 6 inch slabs (kind of like steps) with gravel and sand.  Pump rated for 5000 gph, but will probably get about 3000 after friction loss/head.  We were also thinking about making a type of sand filter out of a couple of apple juice barrels! <... likely not worth doing... will clog very quickly... and w/o a very easy backwashing mechanism will be ignored, abandoned in short order> I have to say I am excited about discovering this site.  So far, my biggest problem seems to be the lack of consistent info.  Example, the pump manufacturers said I need 10 pumps running in tandem!!! <Heeee! Geez!> (I think not)  It's hard to know what to do.  Any help would be appreciated. Noreen <Glad to share. Please make it known if this/these communication/s aren't clear. Bob Fenner>

Aquatic Gardens

Ponds, Streams, Waterfalls & Fountains:
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples

V. 1 Print and eBook on Amazon
V. 2 Print and eBook on Amazon

by Robert (Bob) Fenner
Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: