This is a simple method to get rid of BGA that cost you nothing and
addresses the long term causes of algae outbreaks, poor plant growth.

Remove all BGA you can find, fluff the plants, gravel etc to losen it
and any other detritus/dirt/dead leaves etc. Prune plants good also,
replanting only good stems/tops. After you have done this do a 50%
water change.
Add KNO3 at the ratio of 1/4 teaspoon , ~1.7 grams per 20 gallon of
water.

Cover tank with towle, blankets, trashbags etc
Turn off lights for 3 days.
If you use CO2 turn it off during this time.

Remove after three days, connect CO2 back up and do another 50% water
change.

Add the same ratio of KNO3+ KH2PO4 ot some source of PO4, traces, K+
and make sure the CO2 is up in the 20-30ppm range.

This will prevent most all algae from coming back to any degree and
will cause excellent healthy plant growth.

This method also works for all lighting levels.

You will need to continue to dose the water and do regular water
changes otherwise if the plants run out of some nutrient, the algae
will then take over.
For more info on dosing:
http://www.aquatic-plants.org/fert/e...st_index1.html

Good plant growth is the universal way to achieve algae free tanks
with healthy plants.

regards,
Tom Barr