I have an SFX Micro Thumpinator to do the same job, it's designed to have a very steep high pass filter roll off at that point. There's a video on Youtube that shows how much of a difference it makes to the speaker excursion, without the filter they are all over the place, and with the filter hardly moving at all yet producing the same perceived volume.
Some graphic EQs won't be up to the job as they could have a less steep rolloff and a broader Q point were a 30Hz slider could actually affect freqs around 50Hz also. Sounds like yours has lots of bands if you have separate 25Hz and 30Hz sliders though!