Slow and steady is the name of the game on your sparge and maintaining a level grain bed, with 1" of water on top of the bed is key.

Be sure to use the ball valves on the pump and tank fittings to manage your flow rate in and out of the mash tun. It should match the rate into the mash tun, both set to a trickle as to not disturb the mash bed.

One pro tip is to attach a silicone hose to a side dip tube and run it around the mash bed. This will help keep an even mash bed with out a lot of peaks and valleys that can cause channeling and low efficiency. 

Keep your mash out temp below 180, as close to 170 as possible to avoid the extraction of tannins. If you have the means to change the pH of you sparge water to 5.6 maximum, this also helps keep harsh flavors in the bed and not in your wort.

Finally, mind your grist! If too fine, you can gum up your mash bed and cause channeling. If too coarse, you won't convert enough starch in your mash. A good mix of flour and husk material is key.

Minimum your sparge should take 30 mins, if not 45 to get the best results.