[Supercoley1]

My initial thoughts (and of course can only be guesses on someone else's tank) are:

144W over 50USG = 3WPG - Quite a lot of light.

You do a noon siesta which isn't to hurt algae. It is normally done to replenish CO2 in poorly supplied tanks where the CO2 runs out. thus the hour break gives the CO2 time to build for the second stint. The plants growing well then fights the algae. This method is usually only used on DIY yeast setups as they are notoriously hard to maintain consistent levels.

You only started dosing Phosphorus a week ago.

So my conclusions. For the amount of light oyu have your CO2 is struggling and not enough nutrient (especially phosphorus) is being added. The Seachem dosing schedule won't be enough for a heavily planted high light CO2 enriched setup.

I don't think its the temperature.

Are the ferns the only ones that have problems? Are there any other algae problems within the tank BBA?

With Ferns I tend to be aggressive. very aggressive. If a leaf shows signs of deterioration it comes out. even if the rhizome is then laid bare. They tend to come back much much stronger and thicker too.

AC