Circulation/Turnover Question

[Craig Lambert]

I'm looking at a couple of pumps and have a circulation question. My tank (75G) will be set-up with a 4" dsb, which means the capacity is more like 57G rather than 75. Is that the figure you would use to determine how many times you're turning the tank per hour, or do you stick with the 75G number. (Odd question I know, but the larger pumps requires twice as much juice to operate as the smaller one).

Secondly, based upon the 75G number my turnover would be 17 times per hour with the smaller pump....21 times if I use the 57G figure, and the tank will house LPS and Softies. (No SPS). Does that sound OK?

 

[Woodstock]

17 X is PLENTY for LPS and Softies. I'm having issues with my large euphylia colony due to too much flow right now. It doesn't inflate like it used to with low flow

 

[Craig Lambert]

Thanks Woodstock. I thought it was, but I have forgoten so much over the 2 years I've been away. Someone told me a minimum of 20, and I seem to remember reading a minimum of 10 somewhere. How much circulation did you have going when the problem came up?

 

[Woodstock]

Hummm.. let's see... 700 gph coming up 4' head is equivalent to about 500 gph plus a 400 gph PH; that's a total of 900 gph for my 90 gal which is approx 75 gal (or less) considering the rock and sand displacement. That is about a 12 X turnover rate which was working fine.

I then added another power head of 300 gph onto a wave timer and started having the problems.

 

[Craig Lambert]

That doesn't sound like too much flow. Was your coral "in the line of fire". Maybe just redirecting the powerheads would help you out.

 

[Woodstock]

Ohhh no... it wasn't in the line of fire by any means. The 2nd ph was pointed at the front glass and into the path of the 1st ph's flow... to create turbulance. The coral is just a very large colony. I just moved the colony today to a corner and will try the 2nd ph again.