I would place the second
PH at the opposite end still near the top. If you direct the flow towards the glass, it will cause sufficient turbulance to keep the lower parts of the tank circulated.
I think in your case, this will be of much more benefit. Although having
PH lower in the tank will not harm anything and depending on the amount and denseness of the
LR can help keep dead spots from accumulating excess detritus.
Cheers
Steve