thats a good reactor, and get a maxi-jet 400 with it and you wont go far wrong, fill it approx 1 quarter rowa phos to 3 quarters water to start, 1 bit of advice, make up some sea water add about 2 gallons extra to your system so the water level in the sump is high, then set up the reactor by just hanging it on the side of the sump and dropping the mj400 in the water, and then stick the return pipe into a bucket next to the sump, switch it on and allow the extra water to go through the reactor into the bucket, when the water is back down in the sump to the proper level then just drop the pipe back from the bucket into the sump, this will illiminate any rowaphos or black water in the tank, any problems just let me know