I wouldn't shut off your filter. You could try putting some sort of sponge around the intake to slightly reduce the flow, and prevent plants from getting sucked up into the impeller/filter area.Let's suppose that's not a problem? In that case, if I shut off the filter for maybe 2-3 days until the roots totally took hold, would it cause any further problems?
From my experience it takes a while to get started. Did you cut back the original leaves? I have always found be cutting the original leaves to about 1/2 an inch it started to produce new runners much quicker.Its been two week from when i planted my dwarf hairgrass and there is no sign of growth. Look exactly the same any ideas?