Go to Home Depot and buy the Intermatic Manual timers. Make sure you get the one that has the three prong grounded outlet (they sell the two prong ones as well). I've had NUMEROUS Intermatic digital timers and invariably every one has eventually failed. The manual ones are infinitely more reliable.
As for the Coralife digital timers. They sell them in aquarium stores. House of Fish can get them, but we prefer not to. They have reports of being very unreliable and not the quality we like to carry.
Honestly, the Intermatic manual timers are what we use on all our systems.
ive had a coralife manual and a digital and now a AC jr.....
ive had problems with coralifes one manual one got stuck on and fried a 5gal i had and the digital worked nicely after i got through buying and retutning two of them.
i would buy some ones new and also have a simple single outlet heavy duty manual as a backup.