The Rw-4 is just too strong for this tank with the 24v supply. I used it before when I got it for Christmas as a gift, but even on the lowest setting, using the 24v power supply that comes with the unit, the flow was just too much. I had taken it out and put in the Rio+ that I used in my previous pico, but it's large and unsightly. I started reading and there are a lot of people who have used the 12v power supply swap with much success. I swapped it out, added the RW-4 in place of the Rio, and now I have it on wave mode 1 with slow speed and instead of being on power 1 of 10, I'm on 5 of 10.