Not sure of a product out there to help this but 7.5% interest rates sound like you either refinanced recently?

It can be drained every use (as long as you have an area to drain it properly to so this would be the only hold back) so no chemicals needed or reliance on a Hot Tub maintenance person2.

Also, as mentioned above, this is a great way to start building relationships with small local credit unions and banks which offer the best loan products for investors. 

I've found the product to truthfully be better than an Anderson 100 series window and while I've been fortunate not to have any maintenance issues thus far, my supplier who I've worked with for a few years and trust has made a point of emphasis in saying their warranty response is excellent.

The first prototype will have all specified fixtures, finishes and products as My wife and I like and approve.

If he has only one product in inventory and it’s not selling, then he has no profitable products to offset the loss. 

I’m looking for a list of suggested products (cabinets, flooring, tile, etc) to rehab the interior.

Hey Zane, I work for a production builder.

https://store.biggerpockets.com/products/the-house-hacking-s...

The first prototype will have all specified fixtures, finishes and products as My wife and I like and approve.