My fleas were begging for it, so I let them have it.. sort of

After an hour of trying to figure out why my sprayer won't spray properly I have realized boric acid is not soluble in water. Or is it ?

As i have read over the interwebs, boric acid = borax + salt in a 5:4 mix ratio. There were crystals in the water + boric acid mix (about 200g per 4L) which would clog my sprayers. Would I be guessing correctly those insoluble crystals were the salt ?

I took out the crystals, put the solution in my sprayer and sprayed all over the place. Upon drying a noticeable film of something got laid out where I have done the spraying. Is that the borax ?

And for future referents, should we buy just borax instead of boric acid if we wanted to dissolve it in water ? What ratio borax : water if so ?

  • 1
    Boric acid plus salt will not eradicate an established flea infestation. You need permethrin or some other serious insecticide. Jun 26 '20 at 21:35
  • 1
    Your "reading of the interwebs" does not do your chemistry teacher proud. A compound is not a mixture and your ratios appear dubious even then. Regardless, I would strongly suggest an insect growth regulator (IGR) or a product combining an "adulticide" to kill the fleas and an IGR to prevent the many thousands of eggs from growing into new fleas.
    – Ecnerwal
    Jun 27 '20 at 15:28
  • alcohol might be a better solvent, if you can find any right now...
    – dandavis
    Jun 27 '20 at 19:19

Here is a partial answer: heating the water helped a lot. I have boiled 1.5L, mixed with 0.5L tap water (summer time) and dissolved 100g boric acid in it completely.


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