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I noticed my Amazon swords getting brown spots and starting to yellow. I have a 26 gal. thats 21" deep. I had a 15w 4200K. I replaced with a 15w 18,000K. I also added plant food tabs. The lights were on a timer for 10 1/2 hrs per day. I increased to 11 hrs. I've seen posts that say you need around 3 wpg for healthy plants. I only have .5wpg.

Could someone explain the K values?

Bettafin:
The spots may be due to overfertilization, though this is only a guess on my part.
See if reducing the amount of fertilizer helps. There's a delicate balance between fertilizers and light. Not enough light and your plnats won't photosythesize at the level they need, resulting in too much free fertilizer. Amazon swords are root feeders, so they make better use of solid fertilizers placed in the substrate over liquid fertilizers.

"K" or kelvin is a scale for measuring the color of light. The lower the "temperature", the redder the light. Conversely, the higher temperatures are bluer. Midday sun in the tropics is around 6,000 degrees Kelvin (6,000 K) The high-Kelvin lights are typically used in Marine tanks. As light passes through water, the red photons are blocked, but the blue penetrates. That's why the water looks blue. You may notice a blue tint to your 18,000K light.
According to the research of others, and I guess they're professionals in their field, plants respond best to light which has "peaks" in both the red and blue range.

Sounds like, even though the 'K' of your light may be a bit off, that you're just not providing enough intensity of light to your plant(s). Increasing the photoperiod won't help in this respect. You really want to increase the amount of light by adding more bulbs or switching to a system which will generate greater brightness, such as Power Compact.

Hope this gives you some guidance.

-Wayne

I concure with Wayne. But to add something else. The damaged leaves will not get better. So you should remove them, as they will just start rotting and thus contribute to the bioload. As well, they will be stealing nutrients from the other, still healthy leaves. So it is best to remove the bad stems and leaves from the plant.

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There is always a bigger fish...

Thanks for the input. I've noticed the light is now more intense than before 18000k vs. 4200k. I'm certain that the brown spots are not from over fertilizing. The problem existed before I fertilized. I only put the tabs in last week. I will remove the bad leaves, stems etc.

I also have some sort of cryptocoryne in the tank thats growing well and its much lower which I don't understand why thats doing ok. I've also read that adding more light causes the tank to look washed out. The lighting to me looks good, maybe slightly bluer but more intense than before.

Hi,
What you have done is "shocked" an already weak plant.

Here is a site to help you identify the problem with
the plant and the suggested "cure:"

http://www.csd.net/~cgadd/aqua/art_plant_nutrient.htm

When changing bulbs, it should be done gradually.
In your case shifting from a 4K bulb to an 18K bulb
is like you stepping from a cave into the bright noonday
sun! You would need sunglasses. So too did the plant.
You can do that by placing a piece of cloth that cuts back
on the light between the light and the plant. A kind of
sun screen. Do that for about 2 -3 days, and then remove
it on the third.

As Acid mentioned, you will want to trim off the dying
leaves, and I'd bring the photo period back to 10 hours.

Crypts, are generally considered to be low light plants
and from your comment, the plant is located in just the
right part of the tank. Just enough light. Crypts are
very sensitive to being moved, and to their surroundings.
If disturbed, many times they seem to "melt" (fail). In
that case you will need to trim the dying leaves, and
keep an eye on the central part of the plant removing any
spongey parts (it should be firm). It should recover after
a while (time determined by a variety of things).

Personally, I'd have used a 6700K bulb. To me the 18,000K
bulb washes out the greens.

Frank


Last edited by FRANK at 04-Dec-2004 12:00

-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

OK, I kinda missed that part about over fertilizing. And no, in that part I do not concure with Wayne, sorry Wayne.

As for your Amazon sword plant, I have to question as to how long you have had it? As most of these come in from being grown with the leaves actually coming up and out of the water. Then when they are placed back down submerged, those leaves will die, as new longer and narrower leaves will start to form. If the leaves in question are more rounded with long shafts, I would guess the plant is within months of being completely submerged. It can take several months for these leaves to die and for the new leaves to start growing in. The Amozon Sword does not require high lighting, but does better in higher lighting than you have it under.

You may want to invest in a second light bar over your tank.

_____________________________________________________________

There is always a bigger fish...

Great anology Frank. I believe your right on the plant being shocked. I have had this particular sword for about 6 months. When I first got it some of the top leaves started to die off. I considered it from the intial shock. It had sent off new stems and leaves, but never grew to it's original size about 20". It stayed at 16". About a couple of weeks ago I added 2 new swords. I noticed how bright green they were as opposed to my original one that was more yellowish. So thats when I added my 18k, and increased the light time and added the fertilizer. I do believe the original plant is in shock after hearing Frank's advice. I'm now concerned on if I should change the lighting or leave it alone. I also picked up some fizz tabs that add trace elements and co2. Would this help?

Betta,

Take a look at the back of the January, 2005 issue of Tropical Fish Hobbyist. The advertisement shows the impact of lighting on a fish and has some descriptions of the bulbs that are being advertised. It's a great example of a picture telling a thousand words.

If you have not been fertilizing your plants or if you have not improved your substrate, your sword may be suffering from iron deficiency. Echinodorus sp. are considered to be heavy substrate feeders and need a higher amount of iron than other plants.

__________
"To steal ideas from one person is plagiarism; to steal from many is research."
researched from Steven Wright

I do believe the original plant is in shock after hearing Frank's advice

I'm often shocked after hearing Frank's advice. But it usually proves right in the end.

I think the main thing with lighting (and most aquarium-related issues) is to make changes slowly. how long has the new light been on the tank now? If it's more than a few days, then don't do anything more to the lighting. You and your plants will probably just need to weather the storm and like Acid said, keep a close eye on the plants and keep them trimmed back to healthy growth.

Good luck

the new lights been on for over a week already. I pulled all the damaged vegetation off and reduced the lighting to 10 hrs. I'll just have to wait it out to see if the plant can come back.