coigula wrote in message ...
Hi

I have the growth of a long filimentous type green algae that grows in
threads in the top half of the aquarium. I have little or no other types
of algae clearly visible.


Likely Rhizoclonium.

I run 2 54w full spectrum daylights over a std 55 gallon for 8-10hrs per
day by a timer. Is the source of this algae too much light?

No.

I can
easily raise the height of the suspended light or shorten the duration.
Otherwise plant growth is excellent. I run 80ppm as caco3 alkalinity at
set ph controller to 6.9pH.

Umm that's not enough CO2.
Try lowering the pH to 6.6 with CO2 gas only for this alkalinity.

I use 5 ml Tropica master grow weekly as well.

Try 10-15mls 2-3x a week.

Drew

Plants do poorly when you do not feed them enough, when the plant
growth is poor, the algae come in and grow well.

So add enough CO2 and traces for the plants, you'll likely need some K
and PO4 as well.

Regards,
Tom Barr