Captive portal is showing full every time.

[somendra]

hello All!
I'm having trouble with my pf-sense firewall.in captive portal, it showing 100 or 100+ connected device in captive portal,and this creates trouble for new connecting device like pop up splash page again and again etc.
Rebooting pf-sense box always fix the issue,but i am looking another way rather than rebooting.
Please help me to get this fix.
Thanks.