Any Ideas As To Make An Effective Looking Rapids Tank

over the years i have done many style tanks
but my weak point is rapid style tanks i can never
get them to function like true rapids i am going all
out this time to get the water flowing all one way if any
one as any ideas as to how i can achieve the said effect
i require i am also thinking of making this tank with a sump


                         cheers andy

i think there both excellent i would love
to attempt the first one but there is a great
deal of technology in it with big pumps flow
controllers plus the sheer size of the tank and it
being wedge shaped i could get the tank made
no problem but there must a couple of thousand
pounds worth of computers and pumps so i think i
will go for the second type but go with some larger
power heads and larger bore pipe and some open pore
sponges i have a 3x18x12 tank that i think will do to make
a working model first then see about going to four or five foot
tank