Our Seal Tite koi pond coatings can be applied by brush or roller as well as spray gun. For best results if applying by roller, you will need a roller with as thin a nap as possible, but not a foam type roller. Usually no more than 3/8 inch nap (1/4 inch is better). This helps avoid too coarse a texture. You can also spread out with a roller, then lightly go over the surface with a brush to knock down the texture.
Foam rollers will dissolve if using lacquer thinner, so avoid those.
Also… you may want to plan on tossing any roller or brush instead of cleaning. It may be difficult to fully clean the Seal Tite without a lot of lacquer thinner. At least be prepared to buy another before the next coat.
Hope this helps…Thank you for your business!