Refurbished Diesel Farm Tank - Questions

[varmint]

I've only used the POR black paint, but they seemed pretty adamant about it requiring a top coating? Do you have a float gauge installed? I can tell you from once having a 275 gal. heating oil tank outdoors, but under shelter, that they will draw moisture when the weather conditions are right, so a water filter is needed. I think I would use a biocide additive, as well.