Flowrate needed for 4x2x2

[illumnae]

Hi all, as i've indicated in another thread, i'm in the midst of upgrading my 4x2x2 from a low tech sparsely planted to a moderately high tech with moderate plant density. This tank is running only on an Eheimi 2028, which was rated sufficient for the volume of my tank. However, as the plant mass is going to increase, i've read that the 2028 will not be sufficient to create enough flow for the tank.

could anyone please tell me what rating of powerhead i should add to the tank, and where's the best spot to place the powerhead if my eheim outlet is a rainbar placed horizontally slightly under the water level (won't create enough surface agitation to cause huge CO2 loss)

[illumnae]

anyone can help?

[Aeon]

The recommended flow rate is usually tank volume x 3 or 4. 2028 maybe too low.
My 4x1.5x1.5 using 1300 l/hr i also feel like not enough.

[evolim83]

You should be looking at flowrate of about 3 to 4 times the volume of your tank per hour.

With a 4x2x2 tank, we are looking at volume of about 400L. Therefore, you should be looking at around 1200l/hr to 1600l/hr.

If I'm not mistaken, the output for 2028 is around 1000l/hr.

I would recommend you go for a 2x2028 with both outlets at different ends of the tanks to eliminate deadspots. And with the higher flowrate, you may use the cannisters to push throught external reactor or chiller without having to use a external pump.

[illumnae]

Due to budget and space constraints i'm unable to have a 2nd canister...i was thinking of putting a powerhead in to compensate for the flowrate. would placing a powerhead near where the 2028 inlet is help to compensate for the low flowrate?

[illumnae]

noone at all knows where to position a powerhead to create sufficient flow to avoid algae problems for my tank?

[BFG]

You can always place the powerhead at the other end of the tank.

[illumnae]

thanks for the advice BFG, should i place it low so my hairgrass gets some flow and not get hair algae, or just high like my filter rainbar?

[BFG]

You could experiment on the position of the pumphead to see the desired effect that you want.