Pickup length for heater in deuce tank?

[ida34]

I finally got around to working on my fuel tank. I asked about tapping for a fuel heater in a separate thread. I now have found out that the tank side of the fitting will accept a 3/8 metal line. I know that the pickup tube does not go all the way to the bottom so the heater will get clean fuel and the heater will not run the truck out of fuel. The question is how long is the pickups usually? I measured and get the tank as 16 inches deep. I am thinking about 12 inches or so. Any input is appreciated. I would really like to know what the real deal length is but I am open for a discussion as to length also. Any help or input would be appreciated.

Thanks
Chuck

 

[cranetruck]

IMHO, it's not that critical, a couple of inches above the bottom is what I decided on.
There should be a filter in the line and I may be more concerned about running down the batteries than the fuel...

 

[ida34]

I am just excessive compulsive for doing things stock. I think I am going to go with 12 inches. I got the line today and will be putting my tank back together tomorrow. I also had a problem with the pot metal drain plug breaking a few months ago. I am taking care of that also. The tank was pretty clean but had white stuff in the top half. I assume it was from sitting so long with a half tank at DRMO. I guess the white stuff is algae? Anyone know how to kill it or what it is for sure? I will try to take a pic.