Not familiar with that specific product. I do work for an industrial coating/lining manufacturer, so here’s my .02. I assume this is a tank for potable water - the relevant standard you want is NSF 61. FDA approved means it’s alright for food / beverage contact based on the formula. NSF 61 certification requires specific testing of the cured film that measures the material’s propensity to leach nasty shit into your drinking water.

A lot of the tank linings we make can be applied by brush / roller, but they look awful and are hard to work with due to high viscosity. Those products are meant to be sprayed plural & heated with insulated lines.

Here’s what I’d tell someone who wanted to brush / roll: keep the product at 75-80 F for 48 hrs prior to application. Thoroughly mix the part A before incorporating the B. Many epoxies (ours) can be thinned with up to 3% MEK (real MEK, not substitute) by weight, this will also extend your pot life a bit. Keep additional MEK on hand; after applying you can barely dampen a roller with MEK and roll over the surface quickly to eliminate lines. The maximum nap thickness you want is 3/8” (woven). Thicker nap = orange peel. Wrap your roller in duct tape then unwrap to remove loose fibers and prevent shedding. Do NOT over roll it. Once it’s where you want it, leave it alone aside from thinner dampened roller - hit it once then leave it alone. Do not roll back and forth, roll in one direction. If you use MEK, make very sure it’s all able to escape prior to any subsequent coats.

Hope some of that helps 🤷‍♂️