Water circulation question

[christinaecampb]

I occasionally have been running across references to the importance of the rate of water flow in a tank here on RC. I don't even know what my rate of flow is. How can I figure it out, and what is the appropriate rate for my 80g?

The powerhead in my sump is Odyssea WR 700. It says that the flow max is 2700 L/H. However, I had to decrease the flow with a valve when I installed it, because it was pumping too hard and the tank would overflow at the maximum rate. I set it to pump as hard as it could without overflowing the tank. I just want to make sure the circulation I have is enough.

Thanks!
Christina

 

[marduc]

On your next water change, fill the sump with a known volume of water and time how long it takes the pump to drain it, this will at least give you a decent working approximation.

Either that, or if possible put a gallon jug over the outflow, and time how long it takes to fill that.

 

[christinaecampb]

I opted for the second.

I opted for the second.

It took 20 seconds to pump one gallon. So now do I multiply that by 80 (for the size of my tank), or do I need to figure out how much water is in my sump and include that in the volume?

What is a good circulation rate?

 

[reefnetworth]

hi christina, it would be mutiplied X 60GPH. 20 seconds X's 60 minutes = 1,800GPH. 1,800GPH % 80 gallons = 22.5 times turnover. average for saltwater is 10X's turnover.
JDM...

 

[marduc]

actually 1 gallon in 20 seconds means 3 gallons per minute.. 3 gallons per minute x 60 minutes in an hour is 180 GPH.. that pump is throttled way back huh?

 

[christinaecampb]

Yeah, that's why I was worried about it. Do I need to change something, or is the flow okay? I have it going as far as I can without overflowing the top.

 

[jepuskar]

I'm just a noob, but it sounds like you need another overflow or atleast more diameter on your current drain

 

[christinaecampb]

<a href=showthread.php?s=&postid=9732574#post9732574 target=_blank>Originally posted</a> by reefnetworth
22.5 times turnover. average for saltwater is 10X's turnover.

Are you saying that I have double the flow that I need?! ... or is that half the flow that I should have

 

[jepuskar]

No, that was based on 1800GPH...you actually have 180GPH...which is just over 2x the turnover.