Hi, I am preparing to apply Reward subsurface for control of Pondweed. I plan to do this with a 15 gallon trailer sprayer with a small two nozzle boom and drag hoses.

I have a 3 acre pond, and plan to treat 1/3 at a time at 2 gallons per acre.

I am not sure until I do it once how much product/pressure rate I need to use.

So, I am thinking of adding 2 gallons of reward and 13 gallons of water to my 15 gallon sprayer. Use my boat and keep covering the 1/3 acre until I use it all.

For example, if I only use 1/2 on the first pass, then I make 2 passes.

Thoughts? Also, I assume its ok to dilute the reward? Otherwise it would be tough to requlate the application of just 2 gallons oner 1/3 acre; meaning that I think even on the lowest setting my sprayer would go through the 2 gallons before I finish a first pass on 1/3 acre.

Thanks again for you input!

While I've not use it on pondweed, I've used Reward the past 2 years for an Elodea outbreak in a simlar application process with a 15 gallon gas sprayer dragging weighted application hoses (hydraulic hoses). Works great just have to get the throttle down near idle or it pumps it out too quickly. I've been using a mix of 4oz Reward, 2oz Curtine Plus, 2 oz surfactant per gallon of water. Maximum I would personally go is 6oz Reward per gallon of water. Should be no need to go any stronger, it has been very effective at the ratios listed in my experience with it.
You are correct that you can empty that 15 gallon tank faster than you think (depending on your setup). Fill your system with water first and try it on land, Mine will spray water 10' out to the side of each hose at just above idle. Anymore throttle than that and really shoots it out! Having an extra hand in the boat while applying is a big help.
I can get our 2-acre lake done in about 4 tanks depending on the weed density an how fast I'm going. If you have an algea problem along with the pondweed the Cutrine Plus does well for a relatively small cost while you are applying the Reward. Good luck and any particular questions on my setup feel free to ask. I used the following link for my guide when building my setup:

http://plants.ifas.ufl.edu/manage/research-and-outreach/how-to-build-weighted-trailing-hoses

Water Fowl

Assuming your pump's flow-rate is 1gpm (for example), and using your referenced mix-ratio, you would have 15 minutes to treat 1/3rd (1-acre) of your 3-acre pond at a use-rate of 2 gpa (of REWARD).
If you can effectively cover the designated area in that time-frame, your plan is fine.
If, instead, you think it will take 30-min to cover a 3rd (1-acre) of the pond, then mix 1-gal of REWARD with 14 gallons of water - and disperse two of these tank-loads over a 3rd (1-acre) of the pond.
In both scenarios, you've applied 2-gal of product per treated surface-acre. The ratio of mix-tank water-dilution is irrelevant.
Adjust the mix-ration based on your pump's flow-rate and the amount of time required to travel/cover the designated area.