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FAQs about Circulation Troubles, Repairs for Marine Systems

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Related FAQs: Marine Circulation 1, Marine Circulation 2, Marine Circulation 3, Marine Circulation 4, Marine Circulation 5, Marine Circulation 6, Marine Circulation 7, Marine Circulation 8, Marine Circulation 9, & FAQs on Circulation: Rationale, Designs, Pumps, Plumbing, What's About the Right Amount, & Aeration, Pumps, Plumbing, Make Up Water Systems, Sumps, Refugiums, Gear Selection for Circulation, Pump Problems, Surge Devices, 

Some Conundrums:

Bubbles, leaks, noise!!!, waste heat, screening problems, dust storms, cats and dogs living together, oh my!
Closed-Loop Problem...The "Meager Flow" Issue - 01/23/07
Hello Crew,
<<Howdy Mark!>>
Sorry that I went this route, I do realize how busy you all must be.
<<No worries mate...sometimes ya just gotta ask someone...>>
I did try the Google Search and Website Index first to no avail.
<<Mmm, bet the answer was there for the finding...but let's proceed anyway [grin]>>
Here is my problem, after attending a MAST seminar last April 06 with Anthony Calfo as the speaker, I decided to follow Anthony's advice and make a closed-loop system using his design as posted on this site.
<<An excellent design...though it does seem folks don't quite "get it" at times>>
I have just completed the project and I am a little saddened by the water flow achieved and wonder if a few modifications would help and be worthwhile doing.
<<Ahh, I know exactly what the problem is here...too many or too big outlets/nozzles for the pump utilized...a very common mistake.  Nozzles of 1/2" diameter require "at least" 350gph per nozzle to provide enough "force" at the nozzles to be useful.  Nozzles of 3/4" diameter require at least 600gph per nozzle>>
I have used a Sequence Reeflo Dart pump with the following plumbing: - 2" inlet pipe from tank to pump (Tank not drilled
for CL so it is up and over tank method)(siphon effect) with two 1-1/2" strainers, Overall length of inlet pipe is seven feet(3.5' to first 90-degree bend then up 2' to 180-degree bend then down 1.5' to two 1-1/2" strainers tee-ed off of 2"), - 1-1/2" output pipe from pump to 1/2" outlet pipe on top of tank (28" of head with 180-degree bend to enter 1/2" pipe), - 1/2" pipe with eight loc-line valved outlets.
<<Mmm, I think I'm dizzy now from reading this...or maybe it's just the wine...>>
My first thought is to change the 1/2" outlet pipe to 1-1/2" and still use the 1/2 loc-line valved nozzles.
<<This might help "some">>
Secondly, I would remove the 180-degree bend in the 1-1/2 output pipe and just use a 90 degree bend to attach it to the new tank top 1-1/2" output line.
<<This is a good move...will be equal to reducing head-height by a foot>>
I have attached a crude drawing of the setup that may help you to
visualize it.
<<It does...thank you>>
Any help or suggestions would be greatly appreciated before I go off spending more time and money only to find that my efforts did not help a great deal.
<<Ok Mark, here's the deal...your pump provides 3600gph with zero head...your current arrangement adds a bit more than 5-feet of head.  The pump manufacturer advertises about 2800gph at 4-feet of head...my guess would be more realistically it's closer to  2400gph.  Add to this the pump is meant to be "flooded" (i.e. below water height) and the fact you are "pulling water over the top of the tank" and I'm guessing your actual volume by the time the water gets to the manifold is somewhere in the 2000gph range...maybe less.  Divide this number by the number of 1/2" nozzles and you get 250gph per nozzle...not nearly enough.  But don't take my word for it...cap off about half your nozzles and compare the difference.  The design changes you mention are fine, but they won't solve your problem.  As I see it you will either have to reduce the number of nozzles or get a more powerful pump.  Oh yeah...do consider drilling the tank for a bulkhead to feed the loop if at all possible>>
Many thanks,
Mark Krysztofiak
Materials Management Officer
<<Hope you find this helpful mate.  Eric Russell...humble WWM Crewmember>>
                       
CLOSED LOOP SYSTEM ON 90g TANK               
                       
                       
                       
                       
                       
                       
          1/2" pipe with eight loc-line valved outlets.      
                       
                       
                         
                       
                       
                       
                       
                       
                       
                       
     1-1/2" line from pump to 1/2" outlet pipe            
                       
                       
28" of head with                      
180 degree bend to                 1-1/2" Strainer attached to 
enter 1/2" pipe                 2" pipe.    
                       
                       
                         
Sequence Reeflo