How much air in the tires? Too little air will let the tube get pinched by the rim against hard objects. Those are called snake bite flats.
What causing the flats? Puncture from foreign object? Rough spot on the rim?
A tiny piece of glass or metal sliver can hang around in the rim and give multiple flats if you don't find it.
You narrow down the search by the type/cause of puncture and where in the tire. Always examine the inside of the tire surface carefully for foreign matter or cuts after a flat to make sure there's nothing still there to puncture the new or patched tube.
Your Sand Viper, @Andrew Bogaert is 26 x 4 and you could add nice, wide Mr. Tuffy tire liners along with the slimed tubes to really protect those fatty wide tires. Worth the $$ to prevent a flat while you're riding; better than Slime alone since the liner keeps the objects from ever getting to the tube.