Like you, we live in Texas. Imagine transporting bleach in any spray, squeeze, tilt-dose, etc bottle in your vehicle, every day, 365 days a year, and employing it 2500 times a year. There will be accidents with liquid bleach, and accidents with liquid bleach are expensive and dangerous.I think the best way to treat your tanks is with liquid bleach.
Maybe a livestock board. Horse boards are utterly dominated by complete whack-jobs. If I asked this question on one, I would have a hundred irate replies in a hour.
24 tablets for $30. 1 tablet lasts 12 months.
Something like this maybe?