Comments on: 14.1.1. UV in Depth

By: Daniel

Daniel — Sun, 12 Oct 2025 23:10:13 +0000

Interesting observation: the time of bacteria varies hugely based on the environmental conditions. Most of the published data is from lab culture which is not representative of what’s going on in our tanks.

For example e.coli, which we mostly use as an example in this article, doubles in 20 mins under lab conditions (37C, essentially infinite optimal food source, no bacterial competition or predation from other microbes). When estimate their doubling time in the wild from DNA mutations, it is more like 15 hours. Similar effect for other common bacteria. Our aquariums are neither lab conditions or wild, but the way you run it will move it from one end of the spectrum to the other. If you’re running a cesspool no amount of uv will help you, but if you’re not uv is probably extremely effective.

http://dx.doi.org/10.1098/rspb.2018.0789

By: Osman

Osman — Sat, 07 Sep 2024 04:41:24 +0000

Dear Dave,

Thank you for the article you shared with us. I understand that the UV source chosen and the water cycle rate should be proportional to the reproduction rate of any organism. Still, I wonder about its effect on the eggs of creatures such as worms and flukes.

Kind regards
Osman

By: Dave

Dave — Wed, 24 May 2023 02:18:29 +0000

In reply to Yan. In reply to Yan .... The problem is one of time. In 24 hours a UV will remove most all chlorine and chloramine. And in about 3 hours all the fish will be dead. So UV won't worked to dechlorinate a water change.

By: Yan

Yan — Wed, 24 May 2023 02:05:12 +0000

Have you ever tested UV light for dechlorination?

I know that UV system in pools “eats” a lot of chlorine and chloramine.