Had the 400l upright tank its got 2 of these baffles and I have not felt any effects of the water sloshing about
Yes the holes slots are a baffle of sorts, a baffle is to stop water surge - no water surge means a stable load.The best tanks are the d shaped ones that contain dozens of tubes ( these are proper baffles ) you can also fill the tank with baffle balls or irrigation pipe - these also eliminate water movementDarran