Glosso benefits from actinic light?

From an aesthetic point of view, using actinic lighting to grow ground
plants is just not a good idea unless you want a deep bluish cast
over your tank.

Besides, glossostigma does not need that much light to grow flat
anyways. I will continue to repeat that the way it is planted from
the outset is the key.

This is what I do:

Tease emmersed plant bunch and plant in substrate in medium sized
plugs. Wait two weeks.

Clip off submersed growth. Pull lower portions out and toss. Plant
submersed growth/runners horizonatally in parallels across the substrate.
Watch how it grows. If it even thinks about growing upward, pin it
down with more substrate. Don't be afraid to be rough on it... it is a weed.

In a month, you will have a flat carpet. I have been able to grow a
flat carpet with 2 w/g Power compact lighting on an 18 inch deep
tank. 4 w/g not necessary!

Carlos

To date the best looking Gloss was around 1.5-2.1 w/gal I've ever seen.
That was in a 18" and a 24" deep tank.
Amano also seems to do well with it at low light also, but don't let it get over shadowed.

I really don't think the color is an issue, plants will use light from 400-700 nm. But as far as what it appears like to us is an issue.

Pure water attenuates Red and Far red with peak transmission from sunlight around 500nm(Far red>750= 90% absorption, Red 680 =40%, Yellow 570 =8%, Green = 520nm= 4%, Blue 460= 2%. Reflectance and scattering can account from 6-20% loss.

You need to consider the depth that this occurs also. 1 meter or less does not remove much light, so in our tanks this process does not play much role.

I challenge light meters and other sources for measurements for plants.
These are used at the green portion, 550 nm, not 400-700nm.

Generally aquatic plants are low light plants and have low levels of Luigth compensation points, Hydrillia fro example had a LCP at 10-12 umol, m^2s^1, full sun has about 2000 umol photons, m^2, s^1.

Many aquatic plants can still "grow"(increase carbon content) a 20-30 micromole photons/m^2/s^1

So 1000 times less than full sun.
Most aquatic plants are fine at 100 times the amount of full sun and is consider the euphotic zone for macrophytes.

Any photon will drive photosynthesis at 400-700 nm, but Chl a peaks at 440 and 660nm. But there are other pigments and these can be changed by the plants/algae, and there is also Chl b etc in there as well.

Self shading by canopy forming plants, not allowing the Gloss etc not to be shaded over is very important, some plants don't respond to shading fast, some do. Gloss does.

I'd pass on atinics, you are not going to find any angiosperms in more than 10 meters of water. Most are in 1 meter or less.

Regards,
Tom Barr