Weir / Overflow not getting enough water

Drasi · Jul 3, 2020

So I'm setting up a FW tank, I know this is mostly SW/Reef here, but my setup is no different of a fight we'd all share

I'm not getting enough waterflow into the durso's in my system, the water level is way too low in the weir's.

Beyond "customizing" the weirs and start cutting them, any other recommendations? Maybe I need to go higher with the water volume, but I dont want to overflow the display tank (almost did that earlier!).

I do have it setup so I can adjust the waterflow however I want, but only way to prevent all this, and the noise, its an extremely low flow rate, not at all desired (I really need higher flow rate due to the tank is planned for Oscars - and before people jump on me, its a 220 gallon tank and will be species only)

Below is a pic of the system before I got my sump and everything going - but you can see the weir setup here. I'm almost questioning if I need to cut the top part that has the slots for water to go in the outer weir (I have no idea the actual name of that lol). to get into the overflow section to increase the volume? I just dont want to do it unless I absolutely have to due to it being permanent.

andrewey · Jul 3, 2020

I can't see the back of your plumbing, but is it possible that you are creating a siphon through your standpipes and it is lowering the water to that level? The symptoms of that would be the tank filling up and suddenly the back compartment lowering suddenly with a lot of noise. If you could post a picture of your plumbing and weir directly, it might help.

ca1ore · Jul 3, 2020

Cutting into the weir will not increase the flow, it will simply lower the equilibrium water level in the display. The ONLY way to increase the volume is to increase the pump flow. If you need to raise the water level behind the weir, then increase the height of the durso.

Drasi · Jul 4, 2020

The problem is the higher I increase the pump, the more flow I need coming from the overflow. If I increase the overflow, then the water level gets too low in the overflow and becomes the "sucking/gurgling" sound with lots of bubbles. I cant go any higher on the dorso's otherwise I will be outside the display (and would have to rig up something for more height with PVC) since these came specifically sized for this tank).

I finally pulled the trigger and very very carefully added more water in the display to get it higher on the weirs and was able to actually max out my pump speed (I have a DC pump so I can adjust its speed) and had wonderful waterflow with VERY little noise as I was expecting). The only issue I have with this is if the pump ends up returning too much water, it could overflow the display easily (almost had an incident while I was trying to adjust... eep!). I guess I worry if the overflows get clogged or dont keep up, that it could overflow the display.

K7BMG · Jul 4, 2020

This is a problem every tank has.
The potential of an overflow.
I do not know what pump your using but I solved this issue by installing the float switch on my Varios 8 pump in the tank itself.
I know the float switch is intended for a dry sump and to keep the pump from running dry.

IMO this is more unlikely than the tank overflowing.
In my case my overflow is very inadequate.
Was built in and way to small, very poor design.
Had I known this I would not have bought the tank.

None the less I did overflow my tank twice when first testing.
So I made a bracket to hold the Varios 8 float switch in the tank.
This still allows the intendid purpose of the pump wont run dry, and never allow my tank to overflow.