Thanks bro! I imagined that you had positioned your RW15 in staggered form, which allows the flow to of water to circulate the tank. (Not facing each other).
And i assumed that your RP flow outlet is on the LHS of DT since you have a WP25 blowing from the RHS to mid location. And from your FTS, can see the BB glass on the left side. haha
Are the flows enough for your bottom / sand level ?