Which Filter should i get? ther 170 is 27.89 with shipping and the 330 is 31.98. the 330 is just 4.09 more $$$. so should i go with the 170 or the 330? it will be used most likely on a 20g or 29g tank. if the 330 will be overkill i will just lower the gph which u could to make it have less current. so that wont be a problem both will suit me fine. just want to know what you would buy