how many times have you used this hose to do a water change becuase I have heard that they are putting chemicals in them to keep bacteria from running wild inside them... do you leave the hose outside when you are not using it for water changes... sorry to say that dad is wrong as long as you are filtering it the water should have been fine and if you got the sand at a pet store they always do a really good job with that stuff... your best bet would be to invest in a python they are great and store easily under any larger tank ensuring that it is water change safe...