I just received the newer version of the WP 40 for my 125 gallon. ONE is definitely enough. It eliminated 3 other power heads and I don't even run in on the highest power. Just using "Else" (reef) mode.
The only thing I really don't like about it is the noise is makes when it is randomly changing modes. Sounds like an orchestra in the tank. Literally sounds like a music box in there!. I have read that it will go away in a couple of weeks. I sure hope so!
It's big, but it is better than having three other regular power heads.
Modes:
H: High, constant, non-variable flow (20000 LPH)
L: Low, constant, non-variable flow at a third of the speed
W1: Adjustable pulses at maximum flow rate. (Has a knob so you can decrease and increase the duration of pulses)
W2: Speeds up from low to max in 6 steps, slows down similarly. (w/knob, waves can be lengthened or shortened)
W3: Speeds up from low to max in 6 steps, slows down in 8 steps.
ELSE: Reef Stream Mode, a random flow cycle that randomly increases and decreases speed and duration...mimics natural reef.
Feed: Shuts off for 10 minutes...automatically starts back up.
Lock: You can lock your setting so they don't accidently get bumped, moved, etc.
Speed Lock: You can also lock the maxium speed. 100%, 75%, or 50%. (Works great if you don't want tidal waves!)
Night Mode: Senses when the light goes out and will reduce to half speed.
There are obviously some printing errors. They use "W2" twice, when the second should read "W3"...and Feed..they say just press the button once to go into feed mode, but that just changes the settings. I have to hold for about 4 seconds to enter feed mode.
I ordered mine (2014 version) off eBay from a U.S. seller....good deal, fast shipping:
http://www.ebay.com/usr/powerlink999
Except for the noise...love it so far!