Best spots to put powerhead?

I have a 20 gallon long tsnk with amount 20 pounds of live rock. The rocks are in the middke so there is space un the front and back. I have 2 koralia nano 425gph powerheads. Where are the best spots to put these powerheads ti maximize the flow. I think im starting to see some cyano. Thanks!

 

Nobody can tell you,it's a matter of tweaking trial and error till you and your tank is happy.I would start at both ends facing each other and adjust accordingly until you have good chaotic flow with no "dead spots" and good surface aggitation.

Edit-the 425 nanos are less than impressive imo (I have one myself),you may even find a need to add another.

 

Just do a trial and error and check for dead spots.

 

I had mine on opposite sides of the tank. One shot straight across at the other but the 2nd one was shooting across at the front corner of the tank. I also had one near the bottom just to move water in the low area. No dead spots that I was aware of. Make sure you have good turbulence at the surface.

 

Having the powerheads pointed at each other to create a chaotic random water flow would be a great start.

Dan