Currently I'm setting up a marine tank which is 4 ft by 18 inchs by 2 ft customised tank.
however i have a problem in selecting which chiller to use.
this is my first time using a chiller so i'm not sure which chiller is suitable for my tank.
i'm currently using a 10 years old eheim pump.(i'm not sure which model, but its flow is still quite strong.)

can anyone do recommend which type of chiller is suitable for my tank?
also where can i purchase it?

thank you.