Conventional aeration systems should be placed no deeper than 35 feet. This is due to the fact that you will be compressing atmospheric air that is composed of mostly nitrogen.
Just as a diver gets the bends when going too deep for too long, the same can happen when a standard aeration system is placed below 35 feet.
In a 1.5 acre pond that deep, a single diffuser system will work fine if you be sure to suspend it no deeper than 35 feet. Allow the remaining 11 feet to be a nutrient sink.
You may be able to build yourself a large FAD (Fish attration Devise) out of PVC and sink it to the bottom as well.
It all depends on what type of fish you want to raise in your pond. If you are going for trout, then everyting I just typed will not work for you.
The system will warm the water too much to raise trout.
With a pond that deep and small, normal wind will not be able to circulate water to the depth of 46 feet. You may be fine the first year but rest assure that you will have stratification in the lower regions as well as build up of carbon dioxide and hydrogen sulfide gasses by the end of the season.
The best time to install a destratification / circulation system is before you have a problem. Why do you purchase health insurance before you even get sick?
If you have any other questions, please do not hesitate to post...Have a great weekend!