Re: Diatoms
Well, sometimes people confuse diatoms with brown detritus that the plants themselves produce and which they excrete due their increased metabolism, and which is a direct result of elevated nutrient/CO2 uptake. This is specifically the organic waste that we talk about all the time and is the reason that we are manic about water changes.
The sudden appearance of this condition in your tank does not fit the profile of diatomic algae, which typically occurs as a result of unbalanced or low bacterial loads combined with higher light. This almost exclusively during tank startup and may be prolonged if the lighting stays high. Diatoms are more characteristically cyclic, meaning that they are triggered by, and complete their life cycle during the unbalanced or sterile conditions seen in the immature tank, and then are never seen again. They only rarely ever recur in an established tank. The same goes for the species we identify as GDA (Green Dust Algae).
Subsequent light/nutrient/CO2 imbalances in the tank normally result in the appearance of other specie categories, not these. Of course it doesn't mean that it's an impossibility, only an unlikelihood, so we need to confirm what it is that we are looking at.
What happens when you grab the plant by the scruff of the neck and shake vigorously? Does this result in a cloud of "dust"? If so this is more likely to be the carbohydrates and and other waste produced by the plant itself as it gorges itself on nutrients/CO2. If it's more of a "slurry" then this is more likely to be diatomic.
Why are you having trouble posting pictures? Don't you have a photo upload membership on flikr or photobucket or something like that?
Cheers,