i think its 30 gall each side?im not sure? and i do water changes once a week...thats just the baby tank arkmann i might grow out discus in the double tank i really like them. i deff wanna get alot more discus...love the discus ray combo...my new obsession. thanks for all the comments, in a eek the discus will look even better after they arent so scared and used to the tank. more pics to come as always...