Filter help please??

Hi, I am currently cycling my tank, with my axie reserved and waiting to come home. I was originally sold a filter which was too large for the tank, so I went back to the pet shop and they recommended a fluval u2 which I have now been running for a little over a week. My tank is a 20 gallon long, and I am concerned that the filter is too powerful, as the surface moves a lot, and the plants wiggle around in the water. I bought this filter as it has a spray bar, but even with the bar on, and a plant right in fromt or the filter, the other plants move a little. The filter says a flow rate of 400l/hr which seems a bit high for my 50l tank, and there is no way of turning it down like the first filter I bought. So now I am unsure what to do, I can't take it back, as I have used it, and I can't really afford to buy yet another filter though I will have to if the current is too strong for him. Also, as I am cycling, if I replace the filter, I guess I will have to start again, and then someone else might buy him, as they won't hold him for much longer. I would be grateful for any advice please!

Set the spray bar up facing the tank and that should stop the water moving alot. You could also put some fake plants under or on the ease the flow.

Set the spray bar up facing the tank and that should stop the water moving alot. You could also put some fake plants under or on the spray bay to ease the flow.