Possible Clues:

• Need one tap repaired when the flow is minimal
• Sea phenomenon
• Twice each month one has small ups and downs
• Ocean occurrence
• When high water is low
• Twice-a-month event
• There's no spring to this smallest rise and fall
• Pet Diane trained made little difference in the main
• I tape end (anag.)
• It follows the first or third quarters of the moon