Mite Problem. what insecticide can be used to "dunk" entire plants (sans root ball)?

i read somewhere that someone dunked their plants in insecticide to kill mites, we have been using Safers Insecticidal soap (500ml spray bottle) but cant find any larger containers, we would be looking for about 3 gallons that hopefully dosent cost much.
also after spraying with safers weekly the mites still lived.
does anyone know any websites to buy "bulk" insecticidal soap or a better "dunking" solution?
thanks

google SPINOSAD its organic and can be sprayed onto plants and as a soil drench.



J

PyGanic is a 1.4 percent organic pyrethrum concentrate. Very effective against spider mites, but can by phytotoxic in high doses. I would recommend spraying with kelp a few days after the initial dip to wash off the excess oils on the leaves.
Also, rotation is a strong recommendation (Pyrethrum, Neem, K+ salts, Fish/Oil) on a weekly basis or even shorter if you are infested.
Also, never bring in plants from your buddy's house and keep it clean!