approx. 3 months, they were new.

Ah. Not long. The algae just might be a conincidence, then. It's normal for
a new tank to have varying algae infestations as it gets established. Or, it
could be that after several months, the plants are finally running out of
nutrients.

generally from 4-8ppm.

Pretty low. How do you keep them that low? Is your tank understocked, or do
you do a lot of water changes?

And you
may need to add at least an iron supplement, such as TetraFlorapride.

won't that affect the ph?

Not at all. TetraFlorapride contains only iron and potassium, neither of which
will affect pH. I think you should try it, or a similar supplement. (Liquid
iron.) With your plants and lighting level, you probably don't need anything
else.



Leigh

http://www.fortunecity.com/lavender/halloween/881/