Maximum water turnover

[thallone]

Hi again. This getting back into reefing is not as easy as I had hoped, and my poor mind has lost all kinds of great information in the couple years since I tore down my last setup.

I am interested in opinions on the minimum and , more importantly, maximum turnover for water in a tank. With the pump I have aquiredm it looks like my poor 58g could be looking at over 30 times an hour, if I were to put the whole output of the tank to simple circulation.I have gotten one reccomendation that 15x per hour be maximum turnover.

I am also looking at the idea of a very large sump/refugium setup. I also know that refugium turnover should be low (2-3x per hour max?). My thoughts were to effectively have a 2-zone refugium, with a porous(sp?) separation like multi-layer eggcrate in between.

http://www.angelfire.com/weird2/thallone/refugium.jpg

If the water flow through the actual refuge area is too high, I will add a screen layer between the eggcrate to reduce the barrier turbulence.

[Chuck S]

You are right Refugium very slow water flow.

Now I will object to the opinion of 15X max water flow. Then again it depends on what you want to keep. I have over 20X water flow in most tanks with no problems and could go more. Most SPS corals require constant different changing currents and lots of flow.

[David Grigor]

First off. There are no min/max rules. Like Chuck mentions too many variables and depends on tank, what you want to keep, rock configurations etc. While 15X is pretty easy to achieve in a smaller tank, 15X in say a 300 tank is not as easy and IMO not necessary as long as there are no real dead spots and water movement is sufficiant for your inhabitants....

Also, depends on your definition of what water turnover is, are you talking both in-tank circulation and through the sump or just through the sump ?

Turnover through the sump IMO: should be minimal, enough that if your heater is in the sump that it can maintain the show tank and your water rate is faster than your skimmer output so that skimmer is always picking up water from the oveflow. Anything else IMO is not the most effective way to handle your in-tank circualtion because the head loss etc. of a return pump. Closed loops, internal/external powerheads and all sorts of other options for in-tank circualation that use very little or zero head loss. Plus, your not over taxing your overflows in case one was to get partially clogged or something.