Last week I filled the new tanks to check for any leaks in the corner seams or around the port fittings. I was also testing the gravity fill ports I added to see if they were going to be suitable. They are.
Draining 200 gallons of water makes a mess:
The gravity fill ports will be above the level of the floor over the tanks, but will be used only if the external city connection is damaged or otherwise unusable.
Today I started dry fitting the plumbing and already found a small error in my measurements. The city water connection is centered about 5 inches above the floor, but the shower platform supports come down to within 4-3/4" inches of the floor. I'll have to cut a slot in one of the 2x4s to clear the fill port. I'll also have to add a few elbows to lower the plumbing where it goes under the shower to the water heater/sink.