That's a lot of water to put straight in to the yard. I do 100 gallons of water changes twice a week and it gets my yard pretty damp in the area that I'm siphoning to. 150 a day would keep my yard saturated I think.
I am thinking about it with my tank, but I'll be draining through a wall and in to the gutter that runs under the yard and out to the golf course
My father for his koi pond has a back flush where he would dump it on his lawn and his bushes. It was great until all sorts of flys and critters started coming lol He ended up digging a foot in the ground and running piping to a sewer drain that was 20 feet away. Problem solved.
150 gallons a day is not good on your lawn or property I am telling you if your property slopes it can ruin foundation and many other things. Over time it will.
You also live in New york how are you going to do water changes in the winter? The pipes will freeze immediately dumping 70 degrees or higher water.
Best option is to run into a drain in your home. Safest option. Even a sink drain will suffice.
Trust me I thought about it doing it and I do it out the window but I do 100 gallons a week. In the winter I just use a garden hose to my shower drain. Window is a foot away so convenient but in winter it'll freeze up the pipe quick and plus it'll be icy everywhere.
