If that drawing is a side view, I respectfully disagree on the head that the pump sees. All the pump knows is the differential pressure from inlet to outlet. Assuming the drawing is a side view, the static head the pump sees will be from the surface of the pond to where the water exits the outlet pipe at the top of the waterfall; the plumbing in between doesn't affect that. The dynamic head will always be higher due to the back pressure caused by friction from the pipe, pipe bends, and the partially-clogged filter media.
I know you're pretty smart, so maybe I'm misunderstanding the drawing; does it represent a top or side view?
Last edited by kimini; 08-24-2018 at 05:08 PM.
You're giving me more credit than I deserve , but you're right, and when I was drawing it I thought about going into
what the pond water height was and the difference if the pump was below water level, but I was trying to keep it as
simple as possible, so it's sort of drawn both ways. So the "pond" and the line drawn to the pump is really just to represent
the incoming water to the pump and we'll say that the pump itself is right at pond water level. I think that should make the
lines representing static head of the pump and filter closer to reality.
Thanks kimini for making that clarification.
So, I have my pump situated below water level of the main pond, in the bottom of a barrel holding 55 gallons of water at a time, so the pressure through the pump is significant already. This outlet runs approx 23' total from the pump outlet to the top of the S/G filter where it exits to the waterfall. (There are bends and valves along the way so I know that adds to the head calculation, but for this question we will leave that part out.) Only 5' of this piping is above the waterline of the pond. So, is the head I am supposed to use in my pump's GPH calculation the 23' or just the 5' above water line the water has to go since water primarily seeks it's own level without needing pumped? This will obviously make a big difference in the flow from my pump.
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Last edited by IAmHolland; 09-20-2018 at 01:31 AM.
Here's a good link that discusses how to calculate head. He lays it all out very clearly, but I've read it 6 times and still don't get it.
https://www.koiphen.com/forums/showth...imer-Version-2
If for clarity you leave out the head from the fittings, friction from the water volume pumped, AND media and
only consider the vertical lift you've almost got it; but the lift would be from pond water level to the bottom of
the outlet, since when the barrel is filled from the bottom and it starts dumping out the outlet to the waterfall,
it's only lifting it to the outlet and not the very top of the barrel... but that probably only equates to 6" or so.
Iirc, what Garrett does in his document is takes the whole distance, 23', and measures the distance the pump is
under pond level, i.e. 18', and subtracts it from the from the that 23' which should give you the same 5', or
whatever it is from pond level to bottom of the output of the filter.
I am in the process of installing a 3" RBD into a 55gal SC then to pump. From pump to Bead filter to SG filter back to pond . The SG filter is Birdman design. 2" shower drain intake with 3" clean out and discharge. My question is I have 3" going from RBD through SC and to pump. Should I have 3" from pump to Bead filter to SG filter to 2" shower drain? Or can I use 2" the whole way? Thanks Ken
We have 3" from skimmer to pump then 2" from pump to three S/G's in parallel, works well.
Excellent!! Thank you Bill
I've been running two of these for about 15 months, both based upon Birdman's parts kits. I clean them once a week, and the incoming water flow splits literally right between the two to ensure equal flow. Before cleaning, I always drain a few inches of water to purge anything that might be stuck on the inlet side, then do the usual air purging. Over time, one filter has developed consistently worse flow than the other, even after cleaning. This last week's cleaning shows that things are getting worse; in order to have equal water height on the output side now requires reducing the flow on the "good filter" by about 80%. It's very puzzling about what it could be though. I'd expect that between draining the input side and doing the air purge, the two should fully rid the assembly of whatever's in it. Has anyone else experienced this and what did it turn out to be?
I guess I could take it in steps, that is, take out only the sand on the "bad" filter and see if flow is restored. If not, there's probably a serious blockage on the input side that isn't draining out.
Last edited by kimini; 09-17-2018 at 03:53 PM.
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Last edited by IAmHolland; 09-20-2018 at 12:43 AM.
The electrical conduit sweeps I got have a female end but can I use them if I cut off the female end and leave the other end alone? I'd have to cut 2-1/4" to get the female end off.
...Or would it be better to order this and wait another 2 weeks for completion of my new pond/filter?
https://www.homedepot.com/p/1-1-4-in...E&gclsrc=aw.ds
Just to be be clear, this design of a S&G would call for about 8-9" of chicken grit, right?
A 35" tall barrel, starting at 3" below the outlet, and above the 3" pea gravel/3" regular gravel/3" drain field rock/4" air diffuser piping)
Here's a problem I recently had: just before filling my barrel, I came back to the forum and looked up Birdman's instructions on this thread. I wanted to be sure I did it right. In post #5 it says: "I start out with 3 inches of 1 1/2 inch drain field gravel, then 3 inches of 3/4 gravel, 3 inches of pea gravel, then the sand." That is how I filled my barrel. Then a few days later I was looking over the abbreviated thread of Birdman's build that has all the comments removed:
https://www.koiphen.com/forums/showt...7s+Sand+Gravel
This version calls for "4 inches of 1 1/2 inch drain field gravel, then 4 inches of 3/4 gravel, 4 inches of pea gravel, then the sand."
I'm kind of bummed that maybe I didn't put enough gravel. Which is correct? And will somebody change one of these posts so that both have the correct information.
Pending reply by Steve, I'm pretty sure the lesser dimensions are OK (and maybe preferred). The larger stones are simply there to build up to a size that will hold the sand. I don't think you will find much rock settling between a 3" a 4" dimension. If you used the smaller values, you gain the capacity for 3" more of sand, which will perform better polishing.
I hope you're right. So the sand should come up to 3" below which outlet...pond or waste? I couldn't find that number in my search last week.
Note on the 3" dimension from sand to bottom of waste, any larger and you leave too much "waste water" on top of the sand. Any smaller and you will flush too much sand out.
That said, I've considered a waste cover screen with a hole pattern smaller than the grit I use(d) so that I can add more sand(grit) and not lose any.
Last edited by DangerDave; 04-12-2019 at 09:43 AM.