Parental / Device Controls

the question is are you talking about parental controls or just acces control of firewall rules

the actual parental control is set by opendns ands sort of works but is easily bypassed if the kids know how and your not actually watching them

if however you just want to block internet access by time based schedule its already available

go to the gui and click on the advanced tab

select security and schedule

first ensure the Time zone  is set correctly for your region etc

then

set the time you want the internet blocked

next go to security / access control

turn on access control

select which devices you want blocked

click the block button and then click apply

this should block the devices at the required time from accessing the internet

pete