Amazon Swords killing everything?

car0linab0y

My planted tank as been a huge fail w/the exception of my Amazon Swords. My step-father has a nice planted tank, and said he had to get rid of his Swords because they were killing the other plants. Should I do the same before adding more plants? Thinking of going with hygrophila.
Tank is a 65g 3-footer with a dual T-8 flourecent light (adding more light)
76-78deg f
ph is 6.8-7.0
very low gh/kh

car0linab0y

OK... after google-ing hygrophila, what the store told me was Amazon Swords look more like this picture of hygrophila... but still, could they have killed everything else? Not at home right now, so I can't take a picture of my own until I get back Sunday or Monday.

Attached Images

Hygrophila_lacustris.jpg (81.6 KB, 69 views)

Mikaila31

I think the above pic is Hygo. Corymbosa "narrow leaf". Swords look completely different. Plants don't normally kill other plants. Fast growing plants like both swords and many hygro species can smother other plants. They are good lowlight plants and can out compete other plants for resources. They only harm other plants if you let them take up too much space or block too much light.

bones14

Not all plants are compatible with each other.They can have a sort of biological war with each other releasing chemicals the same as corals can do in saltwater.

Byron

I'm with Mikaila31 on this.

What bones14 is referring to is known as allelopathy, and while there is evidence it exists, it is not, so far as I know, pertinent with species of Echinodorus (swords). Diana Walstad discusses this in a chapter in her book if you want to follow up, and Hiscock and others mention it mostly in passing.

You mention adding more light, do you mean in addition to the dual T8 tubes? I would not recommend this, as you will have more light than the available nutrients and that is going to cause algae blooms. Nutrients and light must be in balance to sustain good plant growth and keep algae at bay.

And speaking of nutrients, are you adding any fertilizers (liquid, root tabs, or nutrient-enhanced substrate material)? Even with the light you have, nutrients sufficient for all those plants (Hygrophila is a stem plant and all stem plants are fast growing plants which means they need sufficient nutrients) is unlikely going to be adequate from the fish food and organics. And you mention soft water, so any minerals that might be in the water will be non-existent or very low. A good comprehensive fertilizer like Seachem's Flourish Comprehensive Supplement for the Planted Aquarium is what I recommend, used once or perhaps twice a week. This, plus a photoperiod of 10 hours a day, with the light you have (assuming it is full spectrum and/or cool white) should be sufficient for good plant growth.

Byron.

bones14

Allelopathy.That's it.It was driving me crazy trying to remember the name.I've come across it several times in my research and Bettababy referred to it in another thread on here awhile back.The original post just made me think of it again.

car0linab0y

Yes, in addition to the existing lighting. I use Flourish twice a week.

Byron

Fine. If you want to post the names of the plants that you say are dying, or better still photos, some of us may have suggestions. Without knowing the plants (except for the Hygrophila in the earlier photos) it's hard to say what the problem might be.

car0linab0y

The other plants are long gone... but if I still have the receipt it'll tell me.
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car0linab0y

I had planned to take some photos when I got home, but the entire tank was green when I got home. Algae took over, but I know my plants are still living b/c the larger of the two that are left is nearly to the top of the tank. I did a 60% water change today, but the water is still too green to actually see through. I plan to do another 50% change Friday. I'm guessing the algae explosion is from leaving the light on and HOB running about half-steam for 10 days.