How about these spikes? Adjustable as you said, which I like lol....
http://www.amazon.com/gp/product/B003IR0FEI/ref=ox_sc_act_title_4?ie=UTF8&m=A3N05JGJHQF6N8
and I upped it to the 320 GPH pump. I'll be using 1/2 tubing, and some spikes to convert to 1/4 tubing....and then to the stakes posted...