First of all I just want to say I'm enjoying this entire build thread immensely, thank you for keeping us updated and including all the detail.
The Auto Top Off.com website is so old it reminded me of spacejam.com (now
https://www.spacejam.com/1996 thanks Lebron...) I was looking for a very similar solenoid solution as my RODI system is relatively close and I have to remove my skimmer every time I want to fill it up my reservoir. How does the product look now that you have it? What other solenoid solutions did you come across in your search?
Thanks!