2700k for ornamental no-plants tank to avoid algae?

[NeonFlux]

Hey guys, I currently have a daylight 6500k 40watt-(10 watt) mini spiral CFL on top of my 250 gallon (not a planted tank) as a night light for several hours during the night until morning and I've noticed it's been causing me some blackish/dark brown algae issues on the decor rocks that are beneath it after three-four months.. It's so very unsightly and it's a real pain to scrub the algae film out.. Other rocks and other areas that are not underneath the lights have no algae and unaffected.

So I've been thinking.. what do you guys think if I lowered down the wattage and spectrum to a LED 2700K 25watt-(3 watt) with a softer, warmer white bulb would help and make a difference to prevent algae from forming or at least slow the growth way down? There's also a daylight LED 5000K 25watt-(3 watt) bulb out there as well.. but it's on the higher 5000K side.

Does lower wattage and the warmer color 2700K spectrum help avoid/prevent/slow algae growth?? What about the brighter, daylight 5000K-6500K spectrum, any difference? Or does it mainly depend the wattage on how fast the algae grows and such?

Hope this makes sense lol I've got not much experience with lighting.

Any advice or input would be awesome!

Thanks guys.

 

[Hendre]

Why have a night light when the fish want to sleep?

Using other spectrums could just give you more algae, I'd stick to around daylight if possible.

 

[Yoimbrian]

Red light is mostly for growing, so avoiding algae growth you'd want blue light. A lot of 24 hour programmed lights, and most reefs, have some light at night to simulate the moon, and they use a mostly blue light.

So ideally get an actual low power blue LED. Or as high of a temperature as possible for a normal light.

 

[Hendre]

2700k is a form of white, blue light will also make an algaepocolipse. This is a warm "yellowish" light.

For less algae use less intense light for shorter periods

 

[NeonFlux]

Why have a night light when the fish want to sleep?

Using other spectrums could just give you more algae, I'd stick to around daylight if possible.

The silver dollars would usually get spooked at night and injure themselves, so that's why I add a night light. The fish would go to darker areas for sleep. Thanks for advice, perhaps daylight.

Red light is mostly for growing, so avoiding algae growth you'd want blue light. A lot of 24 hour programmed lights, and most reefs, have some light at night to simulate the moon, and they use a mostly blue light.

So ideally get an actual low power blue LED. Or as high of a temperature as possible for a normal light.

I see. Interesting about simulating the moon at night. I'll look into blue light. Thanks!!

 

[Hendre]

Moon lights! Of course

As long as you don't go overkill it should be fine