MY ProGrid D.E. Filter say's to add 9 lbs of D.E. ( sticker on tank )
The book say's 9 lbs also, I have read from many sources that say 72sq ft needs 14 lbs ???
Who is correct ???
The book say's 9 lbs also, I have read from many sources that say 72sq ft needs 14 lbs ???
Who is correct ???