Herbie overflows and gravity fed skimmer?

[Delphinus]

Is is possible to combine a Herbie overflow into a gravity fed recirculation skimmer?

[calkrog]

i dont see why not, you are just tuning the overflow by doing the herbie. there is still the same amount of pressure, so providing you have enough head pressure, ie drop from your display to your sump or skimmer, it should work. IMO i should add.

[untamed]

I also agree there is no problem with doing that. In fact, I have a long term plan to do exactly the same thing. I'm guessing that you will have it done before me though.

[Delphinus]

I wouldn't be so sure I've got a long way to go.

I'm just curious because it seems to me that you could put the valve between the overflow and the skimmer, and that would adjust the water level in the overflow, but then you might need a second valve downstream of the skimmer to adjust the water level in there. If that valve is set to a position "more closed" than the upstream valve then it becomes the master valve controlling both overflow and skimmer water levels. I guess if the skimmer was set low enough then this wouldn't be a problem .. ?? I'm just trying to wrap my head around what would happen. Would one valve downstream of the skimmer suffice do you think?

[Joe Reefer]

This may work. Just an idea.

[Joe Reefer]

or maybe you could move the valve on the other side of the tee

[Dale]

Hi Tony,

You can get away with one pre skimmer valve if the overall flowrate is strong enough but for the cost of a valve you will be much happier with the tuning ability of a two valve setup.

This is for a single overflow.
The problem is how to get a predictable flowrate to the skimmer without impeding the displays ability to drain (so the return pump doesn't overwhelm the overflow because of restriction). I have put a "step" in the overflow line to force the water flow first to the skimmer and then allowing it to continue on to the sump. You need a valve pre skimmer to control the flow rate into the skimmer. This, combined with the step will provide a constant flowrate in the skimmer but you won't actually block the overflow. You then need a valve post skimmer to fine tune it.



For a two overflow setup, just dedicate one overflow to the skimmer and the second to drain straight to the sump. Set it up so the first drains sooner than the second. That will provide a constant flowrate to the skimmer without risking a flood.

What you should not do is plumb a single overflow through your skimmer only. If the return pump was stronger than the restricted skimmer flowrate the display would back up and flood and.. if the return pump was weaker than the restricted skimmer flowrate you wouldn't be able to tune the skimmer effectively.

Hope this helps

[Delphinus]

Thanks!

What's the consensus regarding recirculation style skimmers anyhow? The one thing that strikes me as maybe a question mark ... if the skimmer was fed ONLY via the overflow of the main display, then any residual DOC in the water column can only "exit" via the main display overflow. Ie., if the skimmer doesn't fully extract all the "nasties" - the nasties then have to go through the sump, and then randomly through any frag tank and/or refugium back into the main display and back over the overflow for the skimmer to have any "second chances" to extract them. Maybe this is a gross oversimplication of skimmer theory and I'm wrong, but I wonder if this could be construed as a weakness in this idea... over just having the skimmer draw from the sump and return to the sump and recirculate that way.

[calkrog]

dale,

what we are trying to do though is restrict the flow from the display to get the herbie to be quiet. setup one you drew would work, with an additional valve so there is no free flow from the display. am i making sense?

[Dale]

If you mean trying to stop it from gurgling or gulping, the way to do it is to restrict the return pump flow with a valve post pump. I would never restrict the overflow rate myself.