Too Much Current?

Hi all 

Hope this isn't a dumb question, but is there an easy way to reduce current without reducing filtration?

I have a Fluval Roma 200 litre with a Fluval 306 (300 litre) external filter. I want to get a good covering of Amazon Frogbit but there is too much surface agitation for it even with the filter valve half closed. If I could direct the outflow beneath the surface I'm worried the current would be too much for my Cardinals and Harlequins.

Any suggestions?

You could add a spray bar to your outlet. A spray bar spreads the water from your pump over a larger area than the single outlet you currently have, thus reducing/eliminating the current while maintaining the same water turnover through the filter.

If you have plants in the aquarium I'd recommend placing the spray bar well below the surface as too much surface agitation will reduce the amount of CO2 in the tank.

Hope this helps!

Thanks all, I will try the sponge cover as it's the easiest and cheapest to see how that goes.

The Fluval 306 does have a regulator, the white lever in the pic. When it is horizontal the flow is full, when it is vertical the flow is stopped. Fluval recommend no more than a 45 degree angle but the flow is still quite significant.
Surely though, if you halve the flow rate are you not also halving the filtration rate?

http://www.fluvalaquatics.com/cache/media/bluemill/products/Fluval-A20061-106filter-AquaStop-Valvew350-h350.jpg