I keep a few gallon jugs around for my seedling/young plant room ....makes it easy to mix when I first start feeding .... And I also will let my tap water sit out in those jugs for a few days before I water my seedlings with it..... Another trick I use is ...I take a 20oz water bottle and poke holes in the screw on cap ....it's the easiest way I've come up
with to water boxes full of solo cups.....I just go down the line squeezing the bottle.