Plumbing Skimmer line To Settling Chamber!

[maygarden]

I know that some folks totally against running the skimmer to a settling chamber and I understand that! Let's put aside that discussion! If I have to plumb my 3" line skimmer gravity feed to a large 500Gal settling chamber together with a 4" botton drain. And if I don't restrict the flow, which line will get the most flow to its potential? I wanted to know that, so I can decide which line should I install the ball valve to regulate the flow. My guess is that the skimmer line would get the max flow to its protential, so I should put the valve there to restrict its flow to allow more flow to the BD.
What do you think?

[Kent Wallace]

When combining gravity flow components into one chamber it is important to pull enough water out of it to get each one to work. A 3" and a 4" plumbed together needs at least 5000 to 6000 gph to work well. How much are you pulling? What comes through the skimmer line also won't sink so what type of pre-filtration are you using to pull the floating fines out?
The skimmer type is also important. What type of skimmer are you using?

[jimfish98]

if its all gravity fed and being pulled out of the SC by pump, can't each line have its own entry into the SC with a ball valve on each to keep flow in check. This would reduce the lines from competing with each other for flow into the SC.

[Rich L]

You can run them both into the SC but they should;d both come in at a tangent, not direct in with a 90 to send the water around. The later will develop vortexes that will cause the fines to bypass the downward movement of fines heavy enough to be trapped in that particular SC.

At equal equivalent lengths the 4" will move more but those lines are seldom equal. A pipe chart will tell you which.

Once you know that, Kent's questions have to be addressed. Size & type of skimmer & such. you only need enough water over the weir to cause the water surface to move; too much water will pull down into the area just below the surface where there is little waste to justify that water not pulling into the BD

[maygarden]

It will be a pool skimmer. The pump can only pull about 4000 GHP - 4500 GPH out of the SC. That's why I want to know with the limited pump pulling, which line will get more flow when they are competing each other. In the other words, I want to know that normally gravity water will flow more from the skimmer line or from the BB line when sharing the same pump! As I have said, I understand this is not an ideal solution, but I may have to do that temporarily until I can have a separated circuit with separated pumps.

[Rich L]

It really depends on the relative lengths of the two lines. If there is a great deal of difference there may be a problem but I don't expect to see much of an issue here.

I don't have a problem with everything going to the settling chamber but there would be less flow and more fines deposited if the skimmer had a basket on it and it bypassed the SC and tied into the line just before the pump. A large leaf trap mounted on the pump would work if you don't fill it so often that emptying it is a nuisance. Still, it should be removed often so it doesn't contribute to DOCs.

[mtsklar]

It will be a pool skimmer. The pump will only can pull about 4000 GHP - 4500 GPH out of the SC. That's why I want to know with the limited pump pulling, which line will get more flow when they are competing each other. In the other words, I want to know that normally gravity water will flow more from the skimmer line or from the BB line when sharing the same pump! As I have said, I understand this is not an ideal solution, but I may have to do that temporarily until I can have a separated circuit with separated pumps.

As Kent said, the skimmer line needs to be 3". The pool skimmer will need an adaptor or modification to hook up the 3" line.

[maxxreebo1]

3" skimmer line 4"BD with 7800gph pump

[maygarden]

3" skimmer line 4"BD with 7800gph pump

Thanks for posting the pictures. With the 7800GPH pump, I guess you would have no problem to get max flow on both lines. In my situation my pump can only pull 4000GPH-4500GPH. That's where the uncertainty about the flow is on each lines. Both lines are almost the same lenght. Normally the 4" line would pull more water than the 3" line. However, I am not sure if the 4" line BD will gravity flow to its max protental (3000GPH-3500GPH) and only 1000GPH flow thru the skimmer line or the skimmer line will flow up to it protential 1800GPH-2000GPH and leave only 2000-2500GPH flow thru the BD! If the second case is true, then I will need to install the balve valve on the skimmer line to restrict its flow to allow more water thru the BD.

[icu2]

If about equal lengths/fittings, the BD will pull more. But I'm not sure I'd want to put a ball valve on my BD line that's sucking leaves, sticks and all kinds
of stuff off the bottom of the pond.

Do you have a basket in the skimmer? And if so, could you plumb that line directly to the pump and bypass the filter all together?

[boggen]

as soon as anyone says 4" BD over 3" skimmer or vice vs. all it will take is a little bit of something to cause things to flip flop around.

both 4" bottom drain, and 3" skimmer line, both should have a ball valve. you may end up adjusting flow from one or the other pending on season, or muck within the water.

just putting a valve on one of them. and trying not to place valve on the other line is just going to cause you problems. more so when it comes to cleaning the SC. you need a way to shut water off and going into SC during cleaning of it.

ya a knife valve could work as on/off operation. but because knife valves are not geared for adjusting flow rates, you are left with "ball valves".

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as far as trying to fine tune stuff, to how much GPH from one line to the other. there is way to tell, or less you actually have flow rate meters setup. flow rate meters can be costly and require a good amount of straight pipe before and after them, to work correctly.

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what others have noted about getting skimmer adjusted for flow rate, and then leave everything else coming from bottom drain. should be good for ya.