UV Filters - Whats your experience?

[Bradders]

Hi All,

I am interested in understanding how many of us use UV filters - mainly those with a fair amount of fish and leaning towards fish-focused aquariums rather than plant-focused ones.

I had one, removed it (painful to install, slowed flow), re-added it again (more flow pain) and have now taken it off again. (It seems I am not a man who is decisive! 😀 ) Another reason I removed was that I wasn't sure what problems it was "covering up" in the aquarium. But I also appreciate that a well-installed one will help with pathogens and assist other filtration aspects.

Just interested in people's experiences, pros, cons and their overall working belief in using UV in aquariums.

Thanks,
Brad

 

[seedoubleyou]

UV is only really worthwhile if you have a decent steriliser (typically quite expensive) and you’re using it correctly.
i.e. correct flow rates for what you’re wanting to achieve (disease vs algae).

 

[_Maq_]

UV is only really worthwhile if you have a decent steriliser (typically quite expensive) and you’re using it correctly.

My experience seems to confirm that.
Since last summer, I'm using a small internal pumps with small 5 W UV lamps embedded within. I'm rather disappointed. It does not prevent algae. And in one instance, bacterial bloom occurred in one of my tanks and it took several days until the UV lamp removed it. On the other hand, I've got the impression that it generally keeps the water pretty clear.

Could you name an example of what you mean "a decent steriliser"?

 

[seedoubleyou]

Could you name an example of what you mean "a decent steriliser"?

Typically something with more power than 5W and larger than the one you have been using.
For effective sterilising, how powered light and good contact time are important.
This only comes with larger high watt units.

UV is pretty common in the saltwater side of our hobby and a typical UV system would start around £180.

It’s no different to lighting really, there are lights that will just about grow stuff, and lights that really do a good job.

It’s also worth noting that UV sterilising doesn’t prevent algae, it only prevents the algae you already have from spreading, by sterilising the cells.

 

[fredi]

Years ago I used one on a pond, it was 30w, it worked to prevent “green water” as long as the flow through it was not too high, I think “contact time” is the important thing

 

[_Maq_]

Well, thank you both.
Yes I have read it ought to be stronger, contact time of some duration, and it won't touch algae which don't pass through the chamber. Then I saw a handy product for affordable price, and I had to try whether such a half-solution is of any worth. A-quarter-solution, yes, perhaps. 🙂

 

[erwin123]

There are many issues with the effectiveness of inline UV filters. Apart from reducing the flow (flow is King!) , being a source of potential leaks, and taking up more space, I wonder about the 'contact time' if water simply rushes past.

My 'solution' is to use an in-tank UV filter for a few hours after tank maintenance as there will be algae in the water column that needs to be zapped.

As the water flow past the UV bulb in the tank is much slower than in an inline filter, in all likelihood the algae flowing past will have enough contact time with the UV to be 'deactivated' by it.

Thanks to this, I have reduced the amount of GDA on the glass that I need to scrape off. If I simply scraped it off, even with water change, there would still be algae in the water column.

 

[fredi]

Careful with uv, the tank glass (uv lamp tubes are quartz glass), should attenuate it (not uv/a, not sure about optiwhite), uv causes cataracts, dna damage, skin cancer, etc
Be careful out there 👍

 

[erwin123]

Careful with uv, the tank glass (uv lamp tubes are quartz glass), should attenuate it (not uv/a, not sure about optiwhite), uv causes cataracts, dna damage, skin cancer, etc
Be careful out there 👍

thanks for the warning. normally I cover the glass when the UV is on- but removed the cover briefly for the photo 🙂

 

[fredi]

👍
Do you have fish in the tank

 

[seedoubleyou]

View attachment 214302
There are many issues with the effectiveness of inline UV filters. Apart from reducing the flow (flow is King!) , being a source of potential leaks, and taking up more space, I wonder about the 'contact time' if water simply rushes past.

My 'solution' is to use an in-tank UV filter for a few hours after tank maintenance as there will be algae in the water column that needs to be zapped.

As the water flow past the UV bulb in the tank is much slower than in an inline filter, in all likelihood the algae flowing past will have enough contact time with the UV to be 'deactivated' by it.

Thanks to this, I have reduced the amount of GDA on the glass that I need to scrape off. If I simply scraped it off, even with water change, there would still be algae in the water column.

At the risk of being an blahblahblahblah, that UV won’t be very effective.

Why? Because a proper UV bulb couldn’t be exposed like that due to risk of blindness.

 

[fredi]

I would think that if the lamp is having an effect, then it’s producing uv

 

[John q]

I am interested in understanding how many of us use UV filters -

Suspect the answer lies in folks that can't successfully keep planted tanks,and need a band aid.

Interesting none the less to see who employees them. 🤔

 

[fredi]

That’s my thought too
It’s a “band aid” , and not just planted tanks imho

 

[fredi]

By “ planted tanks” I mean tanks which are maintained for the exclusive or predominant “mission” of keeping or growing plants

 

[Bradders]

View attachment 214302
There are many issues with the effectiveness of inline UV filters. Apart from reducing the flow (flow is King!) , being a source of potential leaks, and taking up more space, I wonder about the 'contact time' if water simply rushes past.

I think a feature of UV (in aquarium setups) is that the water goes across the bulb many times an hour. So it might not kill on the first run, but each pass should weaken the content. i.e. if your filter is five times turnover, then that water passes the bulb 120 times in a day. That exposure should have some weakening effect over time and not have to only work on a single pass?

 

[_Maq_]

Suspect the answer lies in folks that can't successfully keep planted tanks,and need a band aid.

Very true. I think the same of CO2 users.

the water goes across the bulb many times an hour. So it might not kill on the first run, but each pass should weaken the content.

My reasoning went similar way. Still, I've described the results (as far as I can comment after few months of use) are less than persuasive.

 

[seedoubleyou]

I totally agree. UV is great if you have the facility to include it in your setup.
But it won’t prevent anything, it’s just an aid in slowing down the spread whilst you tackle the root cause.
It’s not meant to be run constantly.

 

[fredi]

Very true. I think the same of CO2 users.

My reasoning went similar way. Still, I've described the results (as far as I can comment after few months of use) are less than persuasive.

I think a feature of UV (in aquarium setups) is that the water goes across the bulb many times an hour. So it might not kill on the first run, but each pass should weaken the content. i.e. if your filter is five times turnover, then that water passes the bulb 120 times in a day. That exposure should have some weakening effect over time and not have to only work on a single pass?

I don’t think it works like that
I know that from a pond point of view, in a 2,000 gallon pond with a 30w uv, not a lot of effect was observed (after running for 2 weeks) the uv was put on a separately controlled outlet, with the flow much restricted, and was clear in a week (cannot give flow numbers as I really don’t know), all I know is that I was using a large Oase pump rated at around 150w, which was replaced with a more economic pump last autumn

 

[erwin123]

At the risk of being an blahblahblahblah, that UV won’t be very effective.

Why? Because a proper UV bulb couldn’t be exposed like that due to risk of blindness.

Fish lovers, beware: Singapore man blinded by pond's UV lamp

Man partially blinded by UV sterilisation lamp in fish pond while cleaning it. -TNP

www.asiaone.com

Maybe in Europe where everything is tightly regulated they can't be sold, but UV-C fixtures are sold freely in pet stores in Asia...

I would think that if the lamp is having an effect, then it’s producing uv

You are right... i tested by leaving GDA on the glass and seeing the range of the UV - i.e. how much of the green GDA turned white. The range is maybe 10cm though admittedly there was substantial 'dwell'/'contact' time since the GDA was in a fixed position (which again indicates why its more efficient than an inline fixture, because the UV fixture is in a narrow tube and so the full '10cm range' of the UV-C isn't used.