Plumbing to Manifold

[Addicted2ACRO's]

Hello to All....

I need some advice. I have a plumbing question...I would like to add an second internal circulation pump to my existing manifold to increase water flow to my system. Would that be possible without causing possible backflow issues

Thank you ahead for your input

 

[UncommonSense]

It is possible, but fit requires some careful design considerations (I.e. check valves for each pump, correct pump sizing, correct plumbing sizing, etc!)

is this upgrade purely for more flow? If so, does anything stop you from simply using a larger pump? (Assuming the plumbing is sized to accommodate appreciably higher flow, of course!)

 

[Addicted2ACRO's]

Yes...I'm restricted on space for a larger pump with more flow.

 

[Addicted2ACRO's]

BTW...thank you for your quick reply

 

[Addicted2ACRO's]

The pump I'm currently running provides 3600 gph with a maxhead of 23 ft.

 

[troublemaker]

I agree with the advice above, check valves should be used in case one pump craps out, the other would just backflow the other pump, not perfectly, but to a point. Are you sure your plumbing size can handle the increase in flow? If not you sure just creating pressure at the pump.

 

[UncommonSense]

The pump I'm currently running provides 3600 gph with a maxhead of 23 ft.

Wow! Nice!

Yes you can double up pumps to a manifold (aka “parallel pumps”)

This doubles flow at the same operating pressure (max well height)

The pumps should ideally be very closely matched, or identical in performance… they will both require a check valve on outlet plumbing to prevent back flow if a single pump turns off/dies… — serviceable wye style check valves are excellent, but do require regular maintenance to work as intended…

The manifold itself should be capable of handling the requisite flow rates of both pumps (@~10PSI maximum operating pressure)… — look at reducing tees for this application (I.e. tees with 2” parallel sockets, and a 1.5” perpendicular socket); effectively reversing irrigation riser manifold plumbing!

 

[Addicted2ACRO's]

I'm using 1" PVC for the manifold and throughout my plumbing. In regards to your backflow answer if one pump craps out. Currently when the electricity goes out and the one pump stops running, the returns suck water from the main tank until they suck air then no more water syphons into the sump. With 2 pumps and 1 craps out, wouldn't I just still have circulation created by the 1 operating pump?

 

[Addicted2ACRO's]

Since my returns are located near the top of the water surface I shouldn't need check valves

 

[UncommonSense]

I'm using 1" PVC for the manifold and throughout my plumbing. In regards to your backflow answer if one pump craps out. Currently when the electricity goes out and the one pump stops running, the returns suck water from the main tank until they suck air then no more water syphons into the sump. With 2 pumps and 1 craps out, wouldn't I just still have circulation created by the 1 operating pump?

1” is far too small for the target flow rate! You probably don’t need a second pump at all! — start by replacing all plumbing with 1.5”; no restrictive (smaller orifice diameter) points along the fluid path! — smaller diameter returns should be split with tee(s) that are 1.5”, then reduced to 1”-1.25” at both tee outlets!

edit: 2” plumbing could also be used for the main body of the manifold if you do plan to add a second parallel pump later; but your 1” plumbing is choking that existing pump down to roughly 1/3 of it’s max flow rate!

https://www.reef2reef.com/threads/1-pvc-flow-rate.125543/

Since my returns are located near the top of the water surface I shouldn't need check valves

The check valves will be required on each pump outlet because the pumps are the lowest point in the plumbing, and water flows downhill… if one of the two pumps craps out or is unplugged, the second pump’s entire flow rate will just start pushing back out the first pump! — every 1ft of vertical height =.454PSI of hydraulic saltwater pressure!

 

[Addicted2ACRO's]

I thought with the 1" plumbing it would create more pressure.
A few more details to add about the plumbing configuration. The distance from the pump located in the sump thru the manifold to the first return is about 8 1/2 feet, then 6 feet to the chiller, which flows back into the sump and from the manifold to the second return is about another 8 feet. It would have probably been better I mentioned this sooner

 

[UncommonSense]

I thought with the 1" plumbing it would create more pressure.

It will create artificial back pressure at the pump outlet, equivalent to having a gate valve ~60% closed on 1.5” pipe!

You want water volume moving through the plumbing; that is simply restricted at the return locations via return nozzles to create higher pressure! — also, the inherent design of impeller pumps dictates that the majority max out around 10-18psi, at least for the larger pumps typically seen in this hobby!

The water velocity through the 1” pipe is making you loose more pressure as well! (Frictional flow loss from pipe walls/fittings)

A few more details to add about the plumbing configuration. The distance from the pump located in the sump thru the manifold to the first return is about 8 1/2 feet, then 6 feet to the chiller, which flows back into the sump and from the manifold to the second return is about another 8 feet. It would have probably been better I mentioned this sooner

So, you’ll only need the 1.5” for the components of the return pump/manifold plumbing that are seeing the maximum pump flow rate… equipment like your chiller can use a smaller plumbing size (spec based off aforementioned charts, and specific equipment flow needs)!

But, right now, you’re lucky to be getting 1,100-1,200gph out of that pump with the existing plumbing sizing!

 

[Addicted2ACRO's]

So essentially I would have to build a completely new manifold using 1.5" plumbing, but then reduce to 1" for the returns and chiller?

 

[UncommonSense]

So essentially I would have to build a completely new manifold using 1.5" plumbing, but then reduce to 1" for the returns and chiller?

Well, given that your chiller target flow rate is <1,200gph; you’d make a new 1.5” manifold with 1.5” plumbing from pump to manifold.. then probably 1.5” return plumbing, and 1” chiller plumbing! (Return could probably even be 1.25”, but you may as well go a bit big to leave room for more flow later!)

The remainder of the 1.5” manifold could just be 1” outlets, unless you have any other equipment that requires >1,200gph of flow in mind later! (Make that outlet 1.25” for more max flow!)

Edit: your 1.5” return would tee at least once, splitting the flow to each half of said tee to 50%; this is how you get one massive 1.5” return pipe to exhaust through much smaller diameter return nozzles! (Use more nozzles, effectively making one or several return manifolds!)

 

[Addicted2ACRO's]

Unfortunately, but the Tank was only equipped with pre-filter holes of 1". When you say returns your referring to the water returning to the tank or the sump?

 

[Addicted2ACRO's]

Well rebuilding the manifold is gonna take a lot of work...was looking for an easier solution

 

[UncommonSense]

Unfortunately, but the Tank was only equipped with pre-filter holes of 1". When you say returns your referring to the water returning to the tank or the sump?

I’m referring to returning water to the display tank from the sump!

Are you referring to bulkheads in the display tank for water returning from the sump being 1”? If so, how many of these are there?

Or, are you referring to the drains from tank to sump?

 

[UncommonSense]

Well rebuilding the manifold is gonna take a lot of work...was looking for an easier solution

I think we should start from the beginning and see if you actually need nearly 4,000gph of flow to start with!

What size display tank, and sump?

How many drains from the display to the sump, and what size(s)?

How many bulkheads to return water from sump to display tank in total? Size(s)?

 

[Addicted2ACRO's]

Tank is 72x24x24 180 gallons...2x1" Drains and 2x1" Returns...Sump is 75 gallon...all bulkheads are 1" designed by Tank and Sump mgf.

 

[UncommonSense]

Tank is 72x24x24 180 gallons...2x1" Drains and 2x1" Returns...Sump is 75 gallon...all bulkheads are 1" designed by Tank and Sump mgf.

Okay! This is excellent info to have!

So, the current return pump is effectively a bit oversized for this system’s drain capacity… — you’re going to be limited to around 1,300GPH of observed return flow by these!

you’ll mitigate that by directing around half the water to chiller and other equipment, and probably turn the pump down some if possible!

Your manifold should still probably be 1.25-1.5” pipe to take full advantage of the existing pump, with a 1.25” return, and 1” chiller feed!