I just drained my Hayward s244t for the first time. It looks like the filter is only half filled with sand. Is that normal? I wasn’t the one who added the sand so I cannot be sure how much they put in. I suppose I could empty it and add 300lbs myself but if there is another way to be sure I have enough sand I’d prefer to just clean what I have and add a little if needed. Thoughts? Help?