Newly setup tank - September 3: 160W 48" fluor, 2 bags fluorite mixed with plain gravel, box fluorish tabs in gravel. Weekly 25% water changes since starting. Initial dose of Flourish liquid at start 10ml.

Water pH 7.9, KH 14, GH 7, zero nitrites

Fish: 6 medium M. Boesmani, 5 smaller M. Lacustris, 10 otocinclus, 8 amano shrimp (all from previous 75 gallon tank)

Plants: anacharis, small swords, giant sag, ital val, various crypts, narrow leaf hydro, giant rotala, ludwidgia repens, bacopa, liaeopsis novaezelandiae, water sprite, cabomba (plants added in phases, every week or so)

Starting beginning this week, I noticed algae beginning: short thread on val, some blackish smudges on swords, crypts., little bit of green on rocks and tank side. Seemed to correspond to my replacing two old lamps with two new lamps.

Added 12 more otocinclus, 2 giant otocinclus, 22 more amano shrimp

Hook up pressurized CO2 last night, AB reactor: drop every few seconds.
This morning added 110W compact fluor., new philips lamps

What should I be doing so as to not let the algae get out of hand!

More plants, more CO2, don't gas the fish, allow for some surface movement, you can always add more CO2 to make for the loss.

2x a week water change(50-70%) for the first 2-4 weeks and dosing thereafter.
8-10 hours lighting.

Regards,
Tom Barr

So you have 270w over how many liters/gallons?

With high light and CO2 you will need to dose macros...