I have read a lot about excel for algae. It seems the usual assumption is that the other plants do so much better that it starves the algae. This may be partially true, but I thought I would add some light to the issue. The professor I am currently working with just got an experiment approved for publication regarding co2 in fw stream biomes. The experiment was the overall effect of increased co2 on a particular aquatic ecosystem. To spare you details, increased co2 causes a chain of events that significantly increases the amount and size of benthic invertebrates. It has previously been shown that the inverts favorite choice of food is algae. So it stands to reason that since they are larger and more plentiful they are eating more of your algae then they previously were. This is not to say it is the only reason excel works for algae, but it stands to reason it is a solid explanation for a good portion of it. Thought you all might like to know

That is interesting...I am not a planted tank person so I really have nothing to add but that is interesting.

I agree...sounds interesting. I always thought the plants just out fought the algae for nutrients.

Very interesting. I'm sure some plants still do out compete algae for nutrients, but makes me wonder if things like those marimo balls have enough critters hiding in them that they get a good grow on and take care of the algae.

Apparently excel does not work by producing co2. I did a little background work into excels function and it seems there is a fault in my logic. However, I have not given up checking into this. It was done with a co2 injector in an outdoor stream environment. I have to look into a few details of the exact chemistry of excel and see if the injector and the chemistry work closely enough that my hypothesis is reasonable. I will get back to you all soon with more information on this. I know that when I started dosing my tank with excel my green spot algae went away and continues to stay away. I am curious to get a solid explanation for this
Oh and saint, I have a marimo ball in my tank. I didn't start seeing my benthic inverts until that was introduced.

While you're evaluating the test case you may also want to take the lighting issue into consideration. Does full spectrum natural light or any specific part of it play a role in the benthic invert development?

That is something that I have only recently started to consider. I noticed that the marimo ball spread a new type of algae all over my tank. It seems to have only happened since I was forced to change my full spectrum light to partial actinic. I needed new bulbs and they no longer carry exactly what I need, so I thought this would be a good compromise and bring me down from 4wpg to about 3wpg. I have also noticed that there are a few things in my tank (real wood) and a single cryptocorine that will not grow the algae at all, no matter what the rest of the tank looks like. I have begun trying to identify a few common species in my tank and am finding such a huge diversity, setting up and experiment is going to be difficult. I have begun the planning very recently, any more ideas or input that occurs to you would be greatly appreciate. Thank you

Very interesting. I'm sure, some plants do out of competition in seaweed, or nutrition, but I suspect this is the case: these Marimo balls have enough small animals hidden in them, and they get a good algae growth and care.