wow.
thats really small quarters for 2 RES, i feel really bad for them
the standard reccomendation for housing most semi-aquatic turtles is 10 Gallons per square inch of turtle. I am not sure if you are measuring them by full length head to tail or SCL. but from what it sounds like, for right now those little guys need to at least be in a tank of at
least 60 gallons of water. and thats not counting almost 4 times more when they are full grown!
my female res's are about 6.5 and 9.5 inches head to toe, if you will, they both started out in a 125 gallon preformed pond. i felt this was way to small for two turtles, especially one that was full grown and one who was a bit sickly, so for peace of mind i went out and bought them a 275 gallon model, and now im satisfied that they will be more comfortable, less stressed out, less prone to diseases and therefore just more comfy.
i understand that most people do not have room for a 275 gallon pond but a tank that is at least 150-200 gallons would work also.
also seeing that you have a sizable collection of reptiles already and some amphibians, i am quite surprised that you did not already know the housing needs for 2 RES, RES's being a very active and messy animal. i do hope the rest of your collection is being properly housed, for the sake of adaquate mental and physical health.