I had a diesel boat in Florida for three years and if one did not use algaecide like Biobore, the tanks would become petri dishes, slime up, clog everything. Learned that the hard way. It's all a matter of local conditions. Most of us don't want to take the chance and dump in some additives. Lowest temp I've seen here is 9 degrees, and that wasn't for very long, but yes I put in some antigel The stuff allegedly has lubricant to maybe avoid LDI's pump failure, maybe..., and some cetane to offset natural aging.
Seems like cheap insurance. If one uses a lot of fuel and keeps it moving and restocking, yeah, I bet one could use nothing. But that's not the reality for most of us.
Also matters how fresh it is when you get it, and not much control over that other than dealing with the biggest supplier around.
The last thing I wanted was to get a nice new tank and then dump one year old fuel in it. Too bad fuel doesn't come with a dating system that one could dip for age.
We can dip for water, and maybe a few chemicals, but not age.
Oh gosh, should I be asking for organic diesel fuel??
I'd like to run my two diesels on waste cooking oil. I'd have the whole place smelling like popcorn.
My tank cost me about 1400 bucks filled. Seemed like less than ten bucks for a gallon of additives
was decent value. Worst it can do one hopes is do no harm.
When the OP gets his tank installed, would be nice to get pictures. Maybe others who have made tanks this way could show
some installs. We'd all learn. I need to raise mine for flooding. Going to wait until just before refill, say less than 50 gallons, and lift it up and put a concrete structure
under it. Need to do the same thing with my whole house gen. Every once in a great while we get 2 feet of water here, even many miles from the River. When we get over ten inches of rain I start going underwater. House is raised three feet anyway. Barn, equipment and fuel tank right next to main water diversion ditch. So far it has never overflowed, but then I wasn't here for the last major hurricane.
A good side benefit then of a no pump gravity feed tank is you get it high enough to not worry about water.
I'd put a strong oversized step in to hold the guy pumping the fuel though and high enough he can see inside.
I had replaced a seven year old battery in a tractor that was still going and use that to power my DC diesel pump.
I put a smart charger on it once a month and so far, it keeps plugging along. By the time it fails, I'll probably have another battery
from another aging motor. And when they are really dead, I'll take the ten bucks credit on the next one. So battery operated does not always mean
opening up equipment and jumper cabling to run your pump. Just means you need a battery.