55 gallon + 2 55w CFL + Live Plants + Seachem Discus Buffer = Massive algae problem!

I have kept two discus and some other small fish (Cory, 2 brislenose plecos,
12 cardinals, 5 otos) in a 55 gallon for over 2 years now. Over the years,
I made some half-hearted attempts at keeping live plants, mostly Amazon
Swords, but never had spectacular results.

Suspecting my poor plant results were due to anemic lighting, I switched out
the old 40w 48" fluorescent tube for a dual 55w 6000K compact fluorescent
setup from AHSupply, and purchased some more plants. Within a few weeks,
the plants were slowly growing, but the algae was growing much faster. I now
have types of algae I have never experienced before, including this
particularly nasty stuff that carpets the tank every day, and vacuums off
the gravel in sheets. It re-grows every day. It grows on the glass. It
smothers the plants. Every few weeks I have a water-borne algae that I
remove with a Diatom filter.

I am using Seachem Neutral Buffer and Discus Buffer to treat/buffer my tap
water to 6.8pH, and I am aware that the phosphate buffers are probably not
helping. My LFS did not have a suitable phosphate free replacement,
insisted that I am probably not changing the water enough or my tap water
was causing the problem, and offered to sell me RO water for 50
cents/gallon. He insisted that the phosphate buffers were different types
of phosphate, and they would not cause algae growth, I should by his RO
water. I think he's full of sh*t. And I'll be darned if I'm going to
shuttle 5 gallon buckets of water around every day.

My matenence includes daily 10% water changes, adding the Seachem buffers,
Tetra FloraPride, and a tablespoon of seasalt to the change water. I
perform a bi-weekly cleaning of my Fluval 304. The lighting is on for 12hrs
a day (down from 15.)

Is there a good chance that using RO inplace of my tap water would resolve
my algae problem? Can reducing the light duration more help? What would be
a good products to buffer the RO with? Are my water changes not enough, or
are the Seachem buffers a likely culprit? I'm looking for the fastest way
out of my algae problem if possible, including an RO filter purchase if
necessary.

Keep in mind, I like looking at my tank more than I like farting around with
it. I've dropped about $100 on new lighting and I'm not stopping now
Thanks in advance for any advice you can offer.

-Jim