Blacklight/whitelight combination

mjnash84

Hi all,

I am currently running two 18" 15w White day glow bulbs in my aquarium but am looking at changing one of them to a 18" 15w Blacklight, to enhance and add some character to the water.

Was just wondering what effect this would have on the fish and plants and if it would harm them in any way?

Thanks,
MJNash84

iamntbatman

What kind of plants do you have? Black light is UV light, so I would probably be wary of using it all day long.

mjnash84

I have a mixture of plants at the moment, sorry know that doesnt help, what plants would be less harmed to UV light then?!

M

Byron

UV light occurs in the short end of the spectrum with wavelengths of 300-350 nm (nanometers). Plants cannot use this because they only use light between (roughly) 400 and 700 nm, with chlorophyll most effective at capturing light around 650-675 nm. The blue light (400-500 nm) is used because it is most plentiful under water, since blue light travels farther through water and will therefore be stronger than the red.

Peter Hiscock warns that UV light will break down many nutrients, which is detrimental to the plants.

Aside from this, I would be concerned for the fish. Powerful UV sources present a hazzard to our eyes and skin; the fish would certainly be as susceptible. I would not risk this.

karjean

I would stay away also from the black light.

mjnash84

Hi,

Cheers for all the advice, glad I didnt go straight out now and buy a tube. Have deciced that I am going to stick with the white lights for the day and purchase some blue LED lights for the evening/night.

M

Byron

Just in case you're thinking it, a note that plants and fish require some total darkness. Ten hours is natural for them from the tropics. Just ensure that they have close to this of complete darkness. Not having a period of total darkness affects the fish, and may affect plants too depending upon the light type.