Best Light For Red Aquatic Plants ?

[joyban]

Hi Tom,

As I understand that the Red Pigmentation in Echinodorus, Cryptocorynes, Alternanthera reineckii 'Pink', Rotala wallichii etc are caused by Flavenoids, which protect the plants from the damaging effect of ultra violet light (UV-B ?). These plants produced more of this chemical in sunshine than underwater. The red colour was there to protect them from the bright light and specifically from ultra violet light. ( Please Correct me in case I am wrong in thinking that Flavenoids casue the red pigmentation in aquatic plants)

So is it right to suggest that to grow red plants properly one should use lamps that would emit light mostly in between UV Light and the Blue Green Spectrum of Light and very little at the red spectrum because they would reflect them ?

Also has the red colouration in these plants anything to do with any other factor other than the light ?

Best Regards

Sujoy

 

[Tom Barr]

I think you mean more specifically: anthocyanin..........which are part of that group.

They may be for light protection, however............the real question is..........do they have much to do with more light = more red pigment?

Or just for some protection from all light regardless?

That's a much more specific point.

These plants produced more of this chemical in sunshine than underwater.

Really?
So why are those plants you mentioned green above water and red underwater then? Virtually all red aquatic plants are green (or a lot greener at least) above water.

So is it right to suggest that to grow red plants properly one should use lamps that would emit light mostly in between UV Light and the Blue Green Spectrum of Light and very little at the red spectrum because they would reflect them ?

I'd not worry much here, focus on what appears to your eyes the best, not some marketing or other rational. Adding UV is not good for the fish and other things, yourself included. Do plants look good in blue atinic light? Not really, are they redder? No.

If a plant is not naturally and easily red already with good general growth, light, CO2, nutrients, chose a species that is. Otherwise the issue becomes hard to address consistently.

Regards,
Tom Barr

 

[VaughnH]

If you chose to use a light that has little red in it, there will be too little red present to be reflected back to your eyes, and the red plants will not look very red to you. You can only see colors that are in the incident light, being reflected back by the plants and fish. When I switched from 6500K light to GE9325K, which has a lot of red-violet light, my red plants instantly became much redder, as did the red colors of my fish.

 

[Tom Barr]

If you chose to use a light that has little red in it, there will be too little red present to be reflected back to your eyes, and the red plants will not look very red to you. You can only see colors that are in the incident light, being reflected back by the plants and fish. When I switched from 6500K light to GE9325K, which has a lot of red-violet light, my red plants instantly became much redder, as did the red colors of my fish.

So it's not the plants or the content in many cases, it's the light color.

Regards,
Tom Barr

 

[Mikefish]

For what its worth my (limited) experiances with red plants...

I grow some Alternanthia sp. Emerged in a tub with my cryptocoryne collection and I have noticed that the intensity of the red coloration decreases as nitrate levels increase. I have noticed the same with ludwegia repens and arcuata being grown submerged in very shallow tubs.

I also have a few specimens of Echinodorus growing emerged in tubs (red special, ozelot, osiris, ruben) and the emerged leaves are considerably more red than on my submerged aquarium grown specimens. Wether this is due to the leaves being above water or the close proximity of the flouro lighting I don't know. (it is about 6-8" above the plants).

 

[Tom Barr]

I grow many species/(or have), the same listed, out doors emergent.

L acurata is green
A reitnechi is also pale green.
Most red swords are pretty green
Most color variable Crypts are also green.

This is in full intense sunlight and either flourite(KNO3 in solution), soil or recently ADA AS, both of which are rich in NH4.

I would suspect at lower limiting levels of N, you'd see redder colors.

The question is really about the light however.

Intensity, specifically, with emergent growth shows the opposite using sunlight,a full 10X the average highlight aquarium, those plants are green, so are cactus and most desert plants, the deep light limited jungle plants often ar red.

Crypts are deep forest plants submersed in water most of the year, many are red.

Limiting N reduces Chlorophyll, which allows other pigments to show through, but at a price(less growth, potentially stunting some speciesm, but less so with other species).

The best A reineckii I have seen and grown is with rich sediments, and EI, at least colorwise and in lower light, shaded by other plants. Other examples showed at lower light and lower growth rates(non CO2), had excellent reds also.
Another tank was done and used mostly fish waste and low light + CO2, also had vey nice deep reds.

Overall, for our purposes and the topic, the GE bulb seems pretty good for red highlighting. REd plants are nice, but I think too many place undeserved emphasis on the intensity of red, and their expectations.

Most of the expectations are based not on a tank that they saw in person, rather a picture, which may or may not have been touched up with a little post processing.

Even the color setting on the computer screen can affect this.
Aesthetics and color preception is a human issue, much less a plant issue I would think.

Red has been a sign of stress in aquatic plants to me for many years. A few are healthy when deep red, many are not.......

So some conflicting atitudes, advice, questions, light, observations will likely run amuck for some time. Take a look at the ADA tanks and the contest and see what light those folks have, not much really.

ADA AS is rich in N. So is soil etc in natural systems.

Regards,
TomBarr

 

[detlef]

Given the right conditions floating stems of Rotala rotundifolia will take on a nice and intense red if allowed to grow close to bright light. If the same stems grow into areas with much less light intensity they will take on a greenish color. If you force these same stems to grow back into high light areas they'll grow new red leaves again.

This particular species should respond in the same way as often as intended.

Regarding the sometimes very different look of foliage from the same plant can we really compare submergend growth to leaves which developed above water?

Best regards,
Detlef

 

[Tom Barr]

The species variety of R r. is also importnat, we have a extremely red variant, referred to as Singapore Red, and it's much redder........

Likewise, they have green variants of many red plants also..........

Breeding, selection etc at the wholesale level can easily produce better consistn results vs trying to add way too much light, or obsessing over color temps and what not.

I think this is a wiser path(getting a good color variant that we like).

Regards,
Tom Barr

 

[Mikefish]

Thats really interesting, if I understand correctly you are saying that 'excessive' reddening of the leaves is likely to be a sign of insufficient (or low) light levels. Ill try to get couple of photos of some of my emerged swords tomorrow, would love to hear your opinions as to why they are so red.

I must say I am very thrilled to have found a forum, here honest questions get quick thoughtout answers with reasons and advice included, and not the 'because I say it is, or mine is bigger than yours' approach that seems so prevalnt on most forums these days. Have learnt more in 2 weeks of reading these posts then years in other places, worth every cent of the $12.95 entry fee. Many thanks to all involved.

 

[Tom Barr]

Well, not really, at higher light, you have faster growth, so the red pigment appears first.......later followed by the greener pigment, the faster the rates of growth, the more pink to red color you will see in the tips.

So there's a few things going on here.

Limiting N moderately will incur more red, due to less Chl a/b masking the red color also. At higher light intensity/growth rates, maintaining good stable N levels becomes increasingly more difficult. Too much= no red color, too little, stunted plant tips.

This is not an issue of skill, it's just a PITA.

I just pick another species.

Or variant.....

Another observation is that plants running along the top of the water often are redder, growth rate, but also carbon supply, they are now emergent plants getting plenty of CO2 suddenly. They still have the same N, but now have a lot more CO2, C is what makes up most of the red pigment and limits growth rates in most systems, so you end up with redder plants that run on the surface for a few days/weeks etc.

As long as they do not start with too many leaf changes and start to look funny/change etc, then this works nicely.

Then you trim and let these nice red tips grow back up the surface and invite your friends over to marvel at how red your stem plants are

Not the whole story huh?
Photoshop and other things occur also.

Regards,
Tom Barr

 

[Mikefish]

finally got some time to take some pics...'

Is he red / purple color of the new growth on this ozelot a sign it is getting insufficient light ?? or is it normal for emerged growth ?

 

[Tom Barr]

Looks normal to me.

Regards,
Tom Barr