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Rotala macrandra / lighting change

2274 Views 4 Replies 3 Participants Last post by  Tyrone Genade
Hey guys,

Sorry for starting a new thread

I posted this same message on, however no one has posted a reply. So I was was hoping someone in this furom could help me out.

For the last two years I have been growing my plants under a single 96W 10,000K/470nm custom sealife bulb and they have been doing great.

Last week I changed the bulbs to one 55W 6700K and one 55w 9325K. All my other plants are doing great, even better than under the 50/50 bulb (Ludwigia glandulosa, Heterathera zosterfolia, Hemiathus micranthemoides, Glossostigma, Rotala sp. green, anubias Nana, Anubias petite, Eusteralis, Tiger lotus, and Lileaopsis). However, my Rotala macrandra doesn't seem to like the light change.

The new leaves of my rotala turned a really dark pink over a three day period and the lower leaves turned green. It seems as though the growth has stopped also.

Could this be due to a sudden change of the light spectrum from a more blue to a more red spectrum?

Any information that you guys have is greatly appreciated.

Kenneth Takeuchi
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My guess is you are getting more usable light than before with 50/50, and nutrient usage is faster and requires you to dose more. One or more of the nutrients maybe running out. Some plants may show signs of stress faster than others.

My fear is that it is the opposite, the Rotala are now not getting enough light. Compared to the 50/50, the 9325K should actually have less usable light to Rotala macrandra shouldn't it? The 9325K has a huge peak in the red zone, another smaller one in the "yellow" and one in the blue wavelengths. Rotala Being a red plant, reflects light in the red spectrum.

On the contrary to the lack of nutrients, wouldn't my Eusteralis show signs of deficiencies before my Rotala? At least that is the way it has been in the past for me. My Eusteralis isn't showing any signs of nutrient deficiencies, plus it is more colorful (pink red and purple) than it has ever been.

Thanks for the input though, I didn't think anyone was going to respond.

Ken T.
cousinkenni said:

My Eusteralis isn't showing any signs of nutrient deficiencies, plus it is more colorful (pink red and purple) than it has ever been.

Ken T.
There is the clue. In high nutrient tanks, Eusteralis is almost always greener than colorful. I have read posts people stress eusteralis too much with lean nutrient levels, they do get it colorful and then it almost died. Some people like to stress macrandra into red color, but my rotala macrandra is actually blood red in high nutrient levels.
A few days ago I switched from 1 Grolux + 2 Aquastar to 1 Aquastar + 2 Cool White and suddenly the macrandra is looking perky and pushing out nice new leaves. Cool White peak in the yellow and green spectrum...
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