| | Re: Algae and Iron
Interesting. Since the pH and water is the same in both tank halves, pH doesn't really matter. There's also no need for fish.
You will have plenty of other confounds and wiggle room in your reporting, so I would keep it simple and do it as a "pilot experiment." If you get a dramatic difference, then you can trumpet your results and we can enjoy hearing about the details and speculations.
If you get no effect, then I could point to not doing experiment in triplicate. Or that both tank halves were exposed to light at some point during each 24 hr cycle. In the published experiment, there was light in each case, but one set had normal light, the other light where all the shorter, more energetic wavelengths (below 520 nm), which create reduced, algae-stimulating iron, had been removed. Algae didn't grow with the shorter wavelengths, but it did with normal unrestricted light.