Water movement / gyre reversal

[Tonynlo]

From what I remember reading, the general consensus is that water is best moved in one direction, while pumps attempt to occasionally reverse the main gyre. I have a 125G dual corner overflow tank. I don't much like my current aquascape, and wanted to change it up a bit. I am going to set all of my live rock to the left side of the tank, and leave an open swimming area for my fish on the right side.

I was thinking of taking the dual overflow tank, and moving both drains to the left side and placing both of my returns on the right side, forcing the sump water at my rock and coral. My return is a MAG18 running with minimal head loss so I do get a decent amount of flow from it. For water movement, I use 2 Vortech MP40's. I was thinking of placing them both on the same side as my return and running one of them in short 5 second bursts and the other in long pulse mode for about 30 seconds each burst.

Would a single corner overflow be able to take enough water, with both holes set to drain?

 

[der_wille_zur_macht]

What sort of standpipes will you be using and how big are the bulkheads?

How are you gonna keep the "return" overflow box dry and/or prevent water from sitting in it and becoming totally stagnant?

 

[Tonynlo]

What sort of standpipes will you be using and how big are the bulkheads?

How are you gonna keep the "return" overflow box dry and/or prevent water from sitting in it and becoming totally stagnant?

I planned on using a herbie style drain. The bulkheads are 1 inch each, and there are 4 of them.


To be completely honest, I didn't think of keeping the return box dry. Now I'm really glad I asked this question. I have no idea how I would be able to reliably and safely do this. I would rather not, but I could keep the drain on the right side and pump my return through a single bulkhead. I guess I have to think about it a little more.

 

[der_wille_zur_macht]

You could always go over the back for the return(s). At any rate, dropping plumbing size on a return line (or reducing from one to two bulkheads) isn't nearly as damaging to flow rate as dropping size on a drain, since in one case you've got pressure and in the other case there's just gravity.

Off the top of my head I would assume a pair of 1" drains set up as a herbie would do 900-1200 gph. How are things set up today? I had assumed a typical "megaflow" configuration but given that, can't add it up in my head that you have enough drain capacity for a mag 18 to be flat out with no head loss and not be overpowering your drains.

Also, with TWO mp40's on the tank, the contribution thanks to your returns is not exactly significant, so I wouldn't worry if they were not "ideal" as far as the flow pattern you want. Besides, the real concept of a gyre flow model is that you have a circular flow pattern - you can still achieve this with a return in each corner overflow box, you'd just point them to create flow in a circular pattern - i.e. aim one along the back of the tank and point the other towards the front of the tank, and you'll get an overall swirling, circular pattern.