help with flow

yanni · Mar 7, 2023

Hey all,

I’ve got a question regarding flow for my tank, a Waterbox 20. I have my nero mounted on the left side about two thirds up, but I’ve noticed it kinda gets a dead spot underneath itself with minimal flow, which cyano tends to love:/

My options look at mounting another powerhead in the bottom left corner at the back, facing slightly upwards or across at the front to keep flow over the sand and prevent detritus from settling, or I was thinking of moving the Nero to the back wall, in the middle. Roughly where the red dot is in the attached picture, but behind the corals. I’m not sure what would be best, especially that my current flow works everywhere except for that one spot.

Any suggestions ?

lopez052308 · Mar 7, 2023

Do you have it on random flow? If you put it on random and raise the intensity it probably will help some what.

mike550 · Mar 7, 2023

@yanni if you’re getting good flow around the tank except for directly below my guess is that your rockscape is blocking some but I’m not sure any powerhead can hit right below itself.

Left side is fine. Maybe move it either forwards or backwards to try and get more of a “gyre” wave running around the tank. Also if your powerhead has random flow or modes other than constant that will reduce dead spots a bit.

yanni · Mar 7, 2023

lopez052308 said:
Do you have it on random flow? If you put it on random and raise the intensity it probably will help some what.

I’m pretty sure I have it on pulse most of the time, that may be the issue perhaps. Pulses at 70%, then runs at a low 35% overnight

yanni · Mar 7, 2023

mike550 said:
@yanni if you’re getting good flow around the tank except for directly below my guess is that your rockscape is blocking some but I’m not sure any powerhead can hit right below itself.

Left side is fine. Maybe move it either forwards or backwards to try and get more of a “gyre” wave running around the tank. Also if your powerhead has random flow or modes other than constant that will reduce dead spots a bit.

Yeah definitely, I just wanna minimise the dead spots like that. I have it on pulse currently, then constant at night, would trying a high random flow setting work?

I might move it slightly forward so it’s less obstructed by rock and xenia haha, might help move water more

reacclimating 2 the hobby · Apr 3, 2023

What did you end up doing?

yanni · Apr 3, 2023

reacclimating 2 the hobby said:
What did you end up doing?

I ended up increasing overall intensity throughout the day, as well as changing pulse mode for only just before lights on and just after lights off (also slightly while lights ramp up/down), and made my nero go onto a random cycle with high variance throughout the day. It helped moreso with keeping detritus suspended, the cyano has disappeared as well. Got some GHA which seems to love the flow, but slowly working on it with some CUC additions and lowering nutrients!