Hello, have been reading information on the forum but still needing more input. I have two Atlantic stingrays (young) one female and one male in a 110 gallon tank with sand. Have the Rena xp4 . Moving into a larger one soon ! what size do I need to go? only wanting to buy one more time !! also I found this heater (the Fluval E Series heater) hope this will be o.k.? The info has been great on the Monster/ forum Thank you for being here........................ I will post pictures and updates ......... Habit