Actinics in the sump?

[gregzz4]

I feel that 'actinic' claim is bunk
Photosynthetic critters need light in a much different spectrum than 420nm

How does 420nm compare to, say, 6500K ?

[RuGlu6]

My point exactly...

[tang daddy]

Not so sure about atinics but if were talking about growing macro in a sump refuge area the best lights to use are 6400k or red grow bulbs as plants use more red to grow, if you look at grow/veg bulbs on eBay they are usually 6400k or red.

If you're trying to grow sponges in the sump 420nm or no light is best....

[RuGlu6]

Yes , this is what we knew for years,
The question is why would Sump manufacturer
AqueonProducts (not some guy from the corner store) would make such claims?
.
http://www.jlaquatics.com/info/89/Ov...%26+Sumps.html

[sphelps]

Plants use both red and blue light primarily to grow. Algae is similar but various types use different spectrum depending on native depth. Shallow species use more red light, deeper species more blue. The common types we tend to grow will do better with a more red light but some blue could be beneficial.