Hi all when positioning the outlet to filter in the aquarium is there an optimum “spot” for the grill part ie as low as possible or higher the better or aim for middle or does it not matter. hope this makes sense. i am putting in a JBL inlet and outlet in the same corner of the tank and these JBL’s fit in the grove in the top of the tank together. my Oase 250 thermo inlet and outlet are to big. thanks all. (the JBL grill bit can slide in and out of the main pipe so can be set at position that suits)