OK, I need some help here... what can I do to get my pH lower in my tank?

During the day I can get it 7.3 sometimes 7.2.

I am building a new reactor as soon as my mag 3 pump comes in... the mag 3 will be a dedicated pump that will drive my reactor. The output of the reactor will be going into the intake of my return pump from the sump.

My sump has no bio balls, drip plate, etc... I use a 100 micron filter sock to catch the big stuff and a dual sponge filter for the bio load.

Any ideas???

Thanks!

Keith