when i used a digital timer that always happened too me,now i use a cheap plastic timer it works fine all the time,also are you plugging the ballast into a contactor before it goes into the power supply ?
i havnt got a pest problem yet i was just wondering for future reference ,im using a new cocco soil "BIG V" this time round so fingers crossed nothing will hatch lol...thanks guys :)
try your local aquarium shop,they will point you in the right direction if they havnt got them theirselves,or simply look up an hydroponic store close too you :)