[helgymatt]

Doesn't look like iron to me. Maybe K...give it a few weeks and see.

 

[helgymatt]

What would make you think phosphate toxicity? Not likely.... There are pages that show what deficiencies on aquatic plants look like...check them out.

 

[helgymatt]

http://www.aquaticplantcentral.com/forumapc/aquarium-pictures/category/12