That is over-priced, and I do not recommend buying much of anything from aquarium plants. I have had a some bad experiences with them. You can get a milwaukee SMS122 controller, with milwaukee reg/solenoid/pin valve/bubble counter combo set for 161.50 on ebay. I have seen them numerous times, but they are currently unlisted. 2.5 lb bottle is fine if you are ok with refilling it every month, if not every 2 weeks. I personally would do at least a 10 lb bottle, and on my 135 I use a 20 lb.