Since you will have to remove the old uniot to fit a new one, it makes sense to check the in tank unit filter, and possible clean the tank out.
How ever if you have megga bucks ( i dont ) fit a new unit ( and please send the old one to me for xmas please please please )
How ever if you have megga bucks ( i dont ) fit a new unit ( and please send the old one to me for xmas please please please )