I ordered citric acid off of Amazon (it’s great at getting out hard water stains in bathrooms and toilets and helps keep my water softener going well (I add some to the salt tank), also can add some good kick to lemonade)

For every cup of vodka (40 or 60% can’t remember, but prolly 40. Though scientifically 60% would be better) I add 1 to 2 tsp of powdered citric acid. Takes a surprisingly long time to dissolve so you’ll get a quick workout shaking it. I’ve added blue food coloring before to make it more visible in the dispenser to see the level but it’s not necessary at all so I usually skip it.

I make it in a 1 liter bottle which will last a couple months. We have a Bosch dishwasher, refill it… every couple of weeks maybe? I’m not the only one filling it. We do 1-2 loads of dishes a day (4 kids who can’t ever seem to find the cup they JUST used. Probably a parenting problem)

I have no idea if that’s helpful. But I did just lookup a cost by fluid volume- I live in a state with high alcohol tax rates and my cost per fluid oz of my DIY rinse aid is around $0.19 (mostly from alcohol, per fluid oz of citric acid is less than one cent. ) for reference, the small bottle of Jet-dry is $0.58/flOz.