So my builder ran a water line off of our main after the water meter and before it goes into the house. The line has two ball valves on it, one right after it comes off the main and the other right before it goes into the pool plumbing that goes into the filter. I want to hook this to my automation system (Jandy iAqualink) so I can be lazy and add water from my phone when needed. Can I put an irrigation valve after the second ball valve and hook that to my automation? (TLDR: builder forgot to install autofill, this is the "solution")
I found another thread from 2017 where a member did this exact same thing so I'm assuming I can do it, but just wanted to double check before I start buying stuff. What are some things I need to look out for? Will water come rushing out of the pipes and drain my pool when I start to cut things? (I'm assuming it won't because it didn't happen when this line was installed.) I've read about backflow, check valve, vacuum somethings...do I need any of that? I don't know what I don't know. (Crude drawing attached)

I found another thread from 2017 where a member did this exact same thing so I'm assuming I can do it, but just wanted to double check before I start buying stuff. What are some things I need to look out for? Will water come rushing out of the pipes and drain my pool when I start to cut things? (I'm assuming it won't because it didn't happen when this line was installed.) I've read about backflow, check valve, vacuum somethings...do I need any of that? I don't know what I don't know. (Crude drawing attached)
