My 3x turnover was based 0.5 times the rated flow of the cannisters.crazy loaches wrote:People often have 1/2 the turnover (through filtration) or less than they realize.
The following are questions.
I anticipate that rated flows are determined with no or very beneficial flow media in the cannister with short lengths straight tubing.
Placing typical or virtually any clogging of the mechanical or biological filtration media will significantly decrease the flow.
The bends and lengths of tubing observed in practice will also obviously decrease the flow.
Tristan hopefully we can compare notes with respect to wet/dry sump design.
The 2x, 4x, 8x, etc. set forth in the literature are obviously very rough rules of thumb.
The critical parameters in sump design are contact period and rate of flow.
Contact Period
Contact period is obviously a function of the volume available in the sump for biological filtration media.
This concept is not well documented in the literature (ie. I have not located a web page which discusses this concept in even a general form).
Based on my wastewater treatment experience I believe that a contact period of not less than 1.5 minutes is appropriate. This value is way better than a WAG but I could not support this value very well. Obviously this value is a function of the type of biological media employed.
In order to implement this contact period I have significantly more biological filtration media in my sump than would be considered typical.
Rate of Flow
The rate of flow is obviously a function of the area through which the flow is accomplished and hence the shape of the sump is critical.
Based on research several years ago I believe that the velocity through the biological filtration media should not exceed .02 Feet/Second.
If anyone has any critiques or other input concerning the concepts set forth above I would appreciate a post.
TR
), as I have unfourtunately to whatch my time I spent with fish in general.... after all, sooooome day I also want to post my planed tank (isn´t proceeding yet) like many of you already do in a stunning way.