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Glosso benefits from actinic light?

4365 Views 6 Replies 5 Participants Last post by  plantbrain
I've read that actinic lighting (heavy on the blues) will penetrate deeper into the water column than the other colors. Therefore, if you want to get more light on ground plants, actinic lighting should be the key?

Unfortunately, there was some debate on whether algae could make better use of this than plants? Hmm...need to do some digging.
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The only way to get more lighting on ground plants is to up the intensity IME. This means more watts per gallon. IMO actinic bulbs are'nt going to be a good choice for glosso as they are'nt the right spectrum. You need high amounts of red and yellow to get to them as well as blue. And glosso is going to need CO2 of at least 20-30 ppm as well to grow. Actinic bulbs are around 18,000k. Proper plant bulbs are around 6,000 to 9,000k. is an excellent page on what kelvin ratings (k) are all about.
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! :)

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Hey you use co2? I have a tank that is 30" deep and had a hard time with it at 3 wpg. I know though that glosso is a high light plant. What type of lighting do you have?
Anonymous said:
Hey you use co2? I have a tank that is 30" deep and had a hard time with it at 3 wpg. I know though that glosso is a high light plant. What type of lighting do you have?
That was me... :oops:
Yes, at that time, I used DIY CO2 fed into DIY reactor. I was using
two 55 watt Power Compact lights with AH Supply reflectors, in the
5000k region. Don't let the glosso get shaded in the beginning phases
of growth! After that, even in the shade, glosso will only shoot out
horizontal runners.

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.

Tom Barr
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