I found this thread a bit late, but thought I would contribute some additional information.
First it is highly debatable as to whether high levels of Ferts like Phosphates or Iron actually cause algae. There are several hobbiest that have run extremely high levels of both of these nutrients without ever inducing algae. Part of the EI dosing method assumes that it's only deficiencies that cause algae and not excess, so you make sure there is always plenty of all the nutrients available.
Another contributer to Ammonia production is plant decay.
Great work so far.