I am concerned that 2 diffuser for a 1 acre pond is not going to be big enough. What pump are you using? Do you have a pump curve for your pump? What diffusers are you using? I am also concerned about the length if 1/2" runs you are trying to use. Most go with 5/8" weighted line out to the diffusers.

You definately want to use dedicateed lines to each diffuser like wbuffetjr said and use a larger size feed line.

Post your pump model number, pump curve, and diffuser info...we'll look at all together.

Also, figure out how many gallons are in your pond. There are "pond volume calculators" on the web that can help.

Fish on!,
Noel