Yes but it shouldn't be more than a gallon or so. Removing the pickup tube keeps the flow rate from having to lift the water to the valves level. Downside is a little more deadspace and wasted sparge water.
If the valve is on your HLT and your loosing flow sending sparge water to your mash tun, try taking the siphon tube out of the HLT. Just measure the amount of dead space without the insert and adjust the total sparge water volume. Hope this makes sense ...
