OK, I'm set for everything except the electrical.

I got 2 60L (~16 Gal) chemical drums from work.

When buying tubbing, I was torn between clear vinyl and black vinyl. The black blocks UV, but would heat up more. I went with the clear since it was cheaper and plan to run it inside some 1/2" PVC I have on hand. This will reduce heat and UV exposure along with giving it some protection from dogs, kids, etc.

I am considering digging a hole and partly berrying the storage drum to reduce the effects of heat. The area where it will be is almost 100% shaded (between a shed and the house) so I haven't decided if it is worth the effort.

I had to buy a tap for my injector. I couldn't get a firm answer from either the hardware guy or the plumbing guy at Lowes if it was the right one or not. What I'm using as the injector is 1/4" MIP. The tap is 1/4" 18 NPT. After doing some research I'm 95% sure this is right, but I got a 1 1/2" PVC coupler to practice tapping just to be sure.

I should have this ready to go tonight.

I don't think it's much of an issue, but I'm going to order a check valve to install at the injector.

Now the electrical. The pool pump and booster pump are 240V and have intermatic timers. Ultimately these will be changed to connectors controlled by the home automation system, but that's down the road.

The Rola-chem pump doesn't have a normal flow rate adjustment. It has a timer that will run for a time (adjustable) then shut off for a time (relative to the run time).

I'd like to set up the injector pump so that it only has power when the pool pump is running. Is it possible (safely) to step down the 240 to 120 after the pump timer?

My other options for electrical are:
Running 140 from my bathroom vanity to the other side of the wall. Possible downsides to this are that the bathroom isn't on a GFCI (which should probably be updated anyway), and the outside wall is brick.

There is a switch and a timer for landscape lighting in the back corner of the yard. I have no idea where it runs from or what else is connected to it. I went to take look at it a bit ago and the ants informed me that it made a comfortable home, but agreed to move out.

Any opinions or criticisms are welcome.