how many powerheads are needed

Hi Guys i measured my tank and it is a 65 g. I brought two koralia powerheads flow rate 3200l/h and 850 gph is that good enough?

 

I have 2 Koralia 3 powerheads in my 75, one on right side near front, facing slightly down and towards back center of tank, one on left side near back, facing slightly down and towards front center of tank, that eliminates a cyclone effect in tank and does not blow sand around, so just adjust your powerheads to get desired flow. I watch where food goes when I put it in tank to see flow pattern and any areas of too low flow. I'm sure others will get info for you too!

 

I have three K-3s and one K-4 in my 90. Plus 400GPH from the return. You, with just the two K-3s are running 26x turnover. I generally recommend around 50x. I ran 32x for months and ran into problems with cyano. Not enough flow. You could add a few more K-3s and be cool. Do you have any other powerheads and/or a return?

 

ya for my 65g tall, i have a k4 up front and a k2 in the back with the return rated at 750gph. Runs good havent seen any probs and flow is pretty good. Hope that helps