I use them just as a matter of coarse, after gallops, x-country schools or after the x-country phase of an event.
DON"T use them regardless on the QH gelding, he has HYPP N/H and electrolyte is mega dose potassium which could send him into muscle tremors/convulsions.
Very rarely use them as a top dress on feed in winter if a horse is drinking well to offset any possible dehydration.