Ebay. Half inch thick carbon plates are apparently common in glass and solar panel manufacturing. Get them as thick as you possibly can, 1 in is not unreasonable. Also get the biggest plate that you can. Mine has six bolted the whole way around the barrel. Electrolysis works by line of sight, and the plates do degrade over time, so you want as much starter material as you can possibly get in there to avoid having to change plates too often.
You get some sludge that settles out on the bottom, but the water just stays murky black. I have a bung (lol) on it that let's me hook up a garden hose and drain it. Tbh I never change the water unless I have to work on a plate, then I just drain, scoop gunk, refill, and add sodium carbonate. You can get sodium carbonate in bulk from ebay/Amazon. I bought a 5 gallon bucket a while ago. Still have a lot of it.
Eastwood dual voltage gun. Its ok. Good for the money. I used to have the super old school craftsman gun and loved it.
Late to the game here but I would check your fuel pressure, only reason I can think that your fuel trims would be out of wack like that is if the pump is flowing more fuel than the regulator can return. I don't know how the regulator system works on the returnless system but you might need to upsize to something that can maintain the pressure and return more fuel when there's less demand.
Next step for sure. I really hope the in tank regulator is intact...
