I have looked at that model and there isn't a built in way of regulating the water flow.
in engineering if you are going to control a flow from a pump it is always better to restrict
the intake of a pump rather than the output.
you can use a simple c clamp to restrict the flow on the intake of the filter. Just be careful not to pinch the hose too much.

If you can't do that you can make a drip bar across the back of the tank with a pice of PVC pipe and drill some 1/8 holes along the length of the pipe.

you can use one 90 and a end cap and a hose nipple reducer.
and put that on the output to the tank.