I’ve been running two OW-25’s for over three years and love them. Fully directional, super quiet (can’t hear them running), and easy to clean. Multi choices for flow and they sync with each other. Best bang for your dollar.
this review is for the MLW-20 (a knockoff of the nero 3). Works great for my tank (reefer 170) ...actually have it at the lowest setting. Plus it is less than half the cost of a Nero 3. So far...so good.
Good Flow for a great price. Easily programmable. I have 2 units controlled via WiFi with no problem at all.
Average quality. When in pulse mode or high power becomes noisy, noise comes from how speed is regulated and is common to both models I owned. Efficiency decreases over short time, need cleaning regularly. Tiresome to adjust waves and synchronize multiple units over wi-fi. No backup settings after power out. Photodiode of poor quality, and you can't use one diode for all controllers, so you have to place all your controllers in a lightbeam for nightmode to work.
I have the RW-4 in my tank, and it provides great flow. I run the W1 program (short pulse with the dial on the 8th line) - this gives me a decent wave, and my frogspawn loves the sway!
More wave setting options than you could ever need. Pretty quiet.
Not too bad for what you pay.
Have 4 in my tank, never failed. Low noise.
for the price can't complain