Questions about sump and plumbing

[Tanksy]

I made a mistake, sorry. The 1'' pipe has a flow rate of 1799 l/h. The turnover depends on the return pump and the powerheads obviously. My previous calculation was to find out the flow rate of 1 and 2 sizes up from the return pipe; and how low the opening of the pipe should be, below the water surface. Now I understand why the overflow boxes are tall. 

 

Anyway, about the turnover, I redesigned the plumbing and the total length of the return pipe is 90 cm or 3ft. I'm going to use two 45° elbows. So that's another foot. I guess I should add 1 foot for the 90° elbow before the nozzle. That's 5ft (or 1.5m) of head pressure in total.

 

The DCA 2000 has a flow rate of about 400l/h at 5ft. That's... meh.

On the other hand, an Aqua Medic DC Runner 2.3 has a flow rate of about 700-800l/h at 5ft. That's a decent turnover of about 10x. Sounds good?

 

 

So, the return pipe will have the same diameter with the output of the return pump. It's 20mm for the DC Runner. That's 1/2'' for the return pipe then.

The drain pipes will be 1'', just to make sure that it can handle a higher flow. I'm going to use one pump for now though. The DT is only 70l. Don't want to turn it into a washing machine.

 

[Reefkid88]

 With 45's you do not have to add anything,just 90's. Unless you want to be safe and add 6" but its not needed. 

 

  You would be safe with ¾" drain and ¾" or 1" return,I had once found a chart that showed how much pressure each sized PVC can handle,both pressurized and gravity. Let me see if I can dig it up and I will post it. 

 

 Basically if you use 45's,it will create less head pressure therefore not requiring you to have to get a bigger pump to combat the pressure it takes to push the water thru a 90 vs pushing thru a 45. 

[Tanksy]

The return pipe is going through a hole in the cabinet, so I'd have to use two 90° elbows. Instead, I can use two 45° and have the same results.

 

[Reefkid88]

Correct,and less restrictive flow. Thus eliminating some head pressure. 

[Tanksy]

Hi all, 

After a hectic year, I'm finally able to start setting up my nano reef tank.
I'm looking for the right size of pump. But I'm a bit confused. Here's a quick sketch of the plumbing.
 

 

As you can see, the return pipe splits in two, so that I can have two return nozzles.
How can I calculate the head pressure and if I want to have a 3x turnover, what flow rate should the return pump have?
The gross volume of the tank is about 60 l.

Cheers!

[mcarroll]

I can't see your pic for some reason AND you should just open a new thread for your question.

 

But while we're here... 😉 

 

Plumbing diameter and length are the main factors that can influence flow rate.

 

For a relatively short plumbing setup like yours (total length, adding all branches), you can generally use the flow charts that better manufacturers include on the box or on the instruction sheet....a few elbows don't make a real difference.  

 

For a 60L tank, you'd be targeting 180L/H or so if you want 3X.

 

If you were looking at Sicce's SILENT pumps, you'd find this chart....and see that a model ".5" is about right:

From:  https://us.sicce.com/en/products/multifunction-pumps/syncra-silent.html

 

You can use a friction loss calculator like this to model things in detail if you're just curious:

https://www.freecalc.com/fric.htm

 

(Hint:  At your target flow rate, even with 2.4 meters of fairly small 1/2" PVC plumbing and 8 short-radius elbows, you only add backpressure equivalent to  +0.1 feet of head.  Insignificant.  Upgrading to 3/4" PVC eliminates friction losses altogether.)

[Tanksy]

5 hours ago, mcarroll said:

I can't see your pic for some reason AND you should just open a new thread for your question.

 

But while we're here... 😉 

 

Plumbing diameter and length are the main factors that can influence flow rate.

 

For a relatively short plumbing setup like yours (total length, adding all branches), you can generally use the flow charts that better manufacturers include on the box or on the instruction sheet....a few elbows don't make a real difference.  

 

For a 60L tank, you'd be targeting 180L/H or so if you want 3X.

 

If you were looking at Sicce's SILENT pumps, you'd find this chart....and see that a model ".5" is about right:

From:  https://us.sicce.com/en/products/multifunction-pumps/syncra-silent.html

 

You can use a friction loss calculator like this to model things in detail if you're just curious:

https://www.freecalc.com/fric.htm

 

(Hint:  At your target flow rate, even with 2.4 meters of fairly small 1/2" PVC plumbing and 8 short-radius elbows, you only add backpressure equivalent to  +0.1 feet of head.  Insignificant.  Upgrading to 3/4" PVC eliminates friction losses altogether.)

I've reattached the pic in my previous post. Hopefully you can see it now.

The 0.5 pump would be a bit weak. The total -vertical- length of the return pipe is about 1 m/3 ft. Also, there are five 90 degree elbows. According to what I've read, that's 1.5 m/15 ft of head loss pressure. 2.5 m or 18 ft of head loss pressure in total.

 

Am I missing something? I may be wrong

 

[mcarroll]

57 minutes ago, RookieRock said:

I've reattached the pic in my previous post. Hopefully you can see it now.

I see it now.   Nothing too elaborate, so the flow chart should apply pretty well for your case.  Just use at least 1/2" plumbing.....3/4" would be "more perfect".

 

57 minutes ago, RookieRock said:

The 0.5 pump would be a bit weak.

Do you have something more swecific in mind than what you have depicted?  2x-4x is the usual recommended range for return flow.

 

The Sicce "0.5" model would give you about 750L/H at 0m and about 125 L/H at 1m.  Pretty close at 2x.  Still enough to run your filter section just fine....as a bonus, the drain will be SILENT as a ghost at this flow rate.

 

If the flow rate has gotta be ≥3x then upgrade to the "1.0" model, but that's overkill.  

 

The "1.0" is around 750L/H at 1m which is more like 12x...which will make your drains noisy as S*** if you don't throttle it back almost to the flow rate of the "0.5" model.

 

The 0.5 should be fine IMO.  Just use 3/4" plumbing so it can run at its maximum possible.

 

57 minutes ago, RookieRock said:

The total -vertical- length of the return pipe is about 1 m/3 ft. Also, there are five 90 degree elbows. According to what I've read, that's 1.5 m/15 ft of head loss. 2.5 m or 18 ft of head loss in total.

No.   1m (pumping height) is your base "head loss".  Ie From gravity.   The other main thing your pump works against is friction inside the plumbing.   With so little plumbing, you don't have enough to really be a factor in the overall "head loss" number.

 

So, either use the info I gave you (I can help with the calculator if you want to use that for more calculations) or post the info you're talking about so it's not just hearsay.  Otherwise I don't know why they said that, or why you saw that.  🙂 

 

FYI....I actually calculated based on 2.5m of total plumbing and eight 90º Elbows which looks like more than what you have spec'd (but pls clarify if that's wrong).  

 

So the calculated numbers I gave you (+0.1 feet and +0.0 feet, respectively for 1/2 and 3/4 PVC) are very conservative.  We can re-run the calculation if you think you have more plumbing length or whatever.  👍

 

[Tanksy]

Thank you for bearing with me @mcarroll.
Here's where I've read about the head pressure https://www.bulkreefsupply.com/content/post/md-2020-11-how-to-size-a-return-pump.
I think that calculator is for horizontal piping, not vertical. BRStv says that 10' of lateral piping = 1' of head pressure.

 

So, I calculated the head pressure for 1' of piping, using the flow rate of Sicce 0.5.

Liquid Friction Pressure Loss
Pressure Loss (psi):  0.09   Head Loss (ft):  0.2
Line Number:  0  Date:  5/21/2023 Nominal Pipe Size:  0.5 Pipe Schedule:  SCH 40  Flow Rate (gpm):  3 Viscosity (cP):  1 Specific Gravity (water=1):  1 Temperature (F):  77 Pipe Roughness (ft):  0.000016 Actual Pipe ID (in.):  0.622 Fluid Velocity (ft/sec):  3.17 Reynolds Number:  15254 Flow Region:  Turbulent Friction Factor:  0.028 Overall K:  1.3	Piping Length (ft):   1	Pipe Entrance:  0.5 Pipe Exit :  0.5

 

 

And then for 11' of piping.

Liquid Friction Pressure Loss
Pressure Loss (psi):  0.46   Head Loss (ft):  1.1
Line Number:  0  Date:  5/21/2023 Nominal Pipe Size:  0.5 Pipe Schedule:  SCH 40  Flow Rate (gpm):  3 Viscosity (cP):  1 Specific Gravity (water=1):  1 Temperature (F):  77 Pipe Roughness (ft):  0.000016 Actual Pipe ID (in.):  0.622 Fluid Velocity (ft/sec):  3.17 Reynolds Number:  15254 Flow Region:  Turbulent Friction Factor:  0.028 Overall K:  6.75	Piping Length (ft):   11	Pipe Entrance:  0.5 Pipe Exit :  0.5

 

Then for 21'.

Liquid Friction Pressure Loss
Pressure Loss (psi):  0.82   Head Loss (ft):  1.9
Line Number:  0  Date:  5/21/2023 Nominal Pipe Size:  0.5 Pipe Schedule:  SCH 40  Flow Rate (gpm):  3 Viscosity (cP):  1 Specific Gravity (water=1):  1 Temperature (F):  77 Pipe Roughness (ft):  0.000016 Actual Pipe ID (in.):  0.622 Fluid Velocity (ft/sec):  3.17 Reynolds Number:  15254 Flow Region:  Turbulent Friction Factor:  0.028 Overall K:  12.2	Piping Length (ft):   21	Pipe Entrance:  0.5 Pipe Exit :  0.5

 

And for 31'.

Liquid Friction Pressure Loss
Pressure Loss (psi):  1.19   Head Loss (ft):  2.8
Line Number:  0  Date:  5/21/2023 Nominal Pipe Size:  0.5 Pipe Schedule:  SCH 40  Flow Rate (gpm):  3 Viscosity (cP):  1 Specific Gravity (water=1):  1 Temperature (F):  77 Pipe Roughness (ft):  0.000016 Actual Pipe ID (in.):  0.622 Fluid Velocity (ft/sec):  3.17 Reynolds Number:  15254 Flow Region:  Turbulent Friction Factor:  0.028 Overall K:  17.66	Piping Length (ft):   31	Pipe Entrance:  0.5 Pipe Exit :  0.5

 

Do you see the pattern?

[Reefkid88]

Use 45's. Regular and spigot,you'll thank me later. 

[Tanksy]

2 hours ago, Reefkid88 said:

Use 45's. Regular and spigot,you'll thank me later. 

I guess I can replace a couple 90's with 45's to improve the flow. But it all depends on the actual flow rate of the pump I bought, a Jebao VAP-2500.

Maybe it's oversized, but I can throttle it back.

 

 

[mcarroll]

17 hours ago, RookieRock said:

Do you see the pattern?

Yes!  👍. That's what I was telling you....friction losses mostly scale with plumbing length.  Fittings have very little effect in calculations I've made in the past.

 

Try upgrading from 1/2" to 3/4" plumbing and see how the number changes.

 

BTW, I can't tell if they attempted to make any calculations on that link you posted.  Seems like they were just mentioning every rule of thumb you can find on the internet.  They contradict themselves in a few places too.  As resources go, I'd move past that one.

 

IN YOUR DRAWING

You seem to have 1+ meters of plumbing by my eyeball-estimate of your drawing.  Do you think you might have 2m?

 

BTW, after the branch ("tee") you have only 1/2 the flow rate coming through, so friction losses decline proportionately.

 

So your overall run at the peak flow rate can almost be considered 1/2 the actual length.  Then you can run separate calculations on the downstream plumbing segments based on the lower flow rate and remaining plumbing and fittings.  

 

Long way of saying....if you just add up all the length of your whole plumbing run and do the calculation on it, it ends up being a conservative estimate by nature.  (It's very complicated to model the whole run with a lot of fidelity and IME not really worth it in most cases.  But if you want to try for any reason, make sure you set the specific gravity and water temperature, along with the other options you want.

 

Also BTW, if we were talking about higher flow rates, this would be a different discussion.  Friction losses also scale with flow rate.  (We have a low set/target flow rate.  👍)  Friction losses were more relevant before propellor-based powerheads were popular when 100% of tank flow was generated by the return pump, or a closed-loop pump.  Folks were still generally limited to 3/4 or 1" plumbing by "reef ready" tank standards, and may have been trying to do 3-7K L/H in flow.  Sometimes in very long runs from a basement sump, maybe through a closed loop manifold, etc.  In those cases, it was very worth the analysis and streamlining since you could have a massive 16K L/H pump utterly squandered on a "soda straw" plumbing system.  For example, this is what the calculator looks like if you model 16K L/H (66 gpm) through 9 meters of 1" PVC with a bunch of Tee's and 90º's...head loss is massive:

Liquid Friction Pressure Loss
Pressure Loss (psi):  46.91   Head Loss (ft):  105.7
Line Number:    Date:  5/21/2023 Nominal Pipe Size:  1 Pipe Schedule:  SCH 40  Flow Rate (gpm):  66 Viscosity (cP):  1 Specific Gravity (water=1):  1.025 Temperature (F):  79 Pipe Roughness (ft):  0.000016 Actual Pipe ID (in.):  1.049 Fluid Velocity (ft/sec):  24.51 Reynolds Number:  203955 Flow Region:  Turbulent Friction Factor:  0.017 Overall K:  11.33	Piping Length (ft):   30 Short Radius Elbows:  10 Tee Flow Through:  2

 

Just switching that setup from standard 90º fittings to "long radius" 90º fittings looks like this...still a lot of head loss, but significantly better, even without changing anything else:

Liquid Friction Pressure Loss
Pressure Loss (psi):  41.2   Head Loss (ft):  92.9
Line Number:    Date:  5/21/2023 Nominal Pipe Size:  1 Pipe Schedule:  SCH 40  Flow Rate (gpm):  66 Viscosity (cP):  1 Specific Gravity (water=1):  1.025 Temperature (F):  79 Pipe Roughness (ft):  0.000016 Actual Pipe ID (in.):  1.049 Fluid Velocity (ft/sec):  24.51 Reynolds Number:  203955 Flow Region:  Turbulent Friction Factor:  0.017 Overall K:  9.95	Piping Length (ft):   30 Long Radius Elbows:  10 Tee Flow Through:  2

 

Interestinghly, if you use two 45º elbows to "make" a long radius 90º, it doesn't scale the same...so get long radius 90º's if this is a real concern (aka long sweep 90, or elbow):

Liquid Friction Pressure Loss
Pressure Loss (psi):  46.91   Head Loss (ft):  105.7
Line Number:    Date:  5/21/2023 Nominal Pipe Size:  1 Pipe Schedule:  SCH 40  Flow Rate (gpm):  66 Viscosity (cP):  1 Specific Gravity (water=1):  1.025 Temperature (F):  79 Pipe Roughness (ft):  0.000016 Actual Pipe ID (in.):  1.049 Fluid Velocity (ft/sec):  24.51 Reynolds Number:  203955 Flow Region:  Turbulent Friction Factor:  0.017 Overall K:  11.33	Piping Length (ft):   30 45 degree Elbows :  20 Tee Flow Through:  2

 

There are different styles, but for example, a long radius 1/2" elbow: 

 

Normal 1/2" elbow:

 

In general, and getting back to your case, if you're just moving water from the sump to the tank for filtering purposes, a standard pump can be spec'd with the provided flow curves.  

 

If you go with the Silence pumps, you'll have to throttle the "1.0" a lot, but it should work.  I imagine it'll be fine even at a really low flow rate, but gotta remember that all pumps require water flow to cool the impeller and the motor.  It's possible to shorten an impeller's life by running it hot.  (But then impellers are usually very inexpensive parts.)

 

If you go with the "0.5", then your flow multiple will be at the lower end of the suggested range, but IMO that's fine.  Your drain system will be inherently more quiet and the pump's working lifespan will be maximized.

[Tanksy]

@mcarroll 

I'd rather go with a DC pump, that's why I ordered the Jebao VAP-2500. I can tune the flow accordingly and it's -supposedly- dead silent.
As for the calculator, like I said, it's for pressure loss of horizontal piping, not vertical head loss.

Check this out http://www.reefcentral.com/forums/showthread.php?t=2161556. 

[mcarroll]

4 hours ago, RookieRock said:

@mcarroll 

I'd rather go with a DC pump, that's why I ordered the Jebao VAP-2500. I can tune the flow accordingly and it's -supposedly- dead silent.

I'm not familiar with them and that model doesn't come up at all on a Google search!  As long as it's a really small pump, I'd guess it'll work out.  🙂 

 

Don't over-sell yourself on "DC pumps" though.  They're fine as far as they go, but it's unlikely they are as different from "AC pumps" as most folks would like to think....and the differences that are real aren't all good.

 

4 hours ago, RookieRock said:

As for the calculator, like I said, it's for pressure loss of horizontal piping, not vertical head loss.

Check this out http://www.reefcentral.com/forums/showthread.php?t=2161556. 

I'm not sure what your'e referring to on either point.

 

The calculator I've been pointing you to calculates friction loss.  

 

Friction loss is pressure loss from water rubbing up against the inside of the pipe.  Irrespective of verticality or horizontality.  

 

You'll notice that the results are expressed both in loss of PSI as well as "head loss" in feet.    Head loss is easier for us to use because you simply use addition to combine that number with the vertical pumping height from the sump to the tank.  Easy.

 

I'm not sure what you're referring to in the RC link...I see that it's about analyzing pumps, but I don't see anything especially relevant to your situation...was it something specific that maybe you could quote here?

[Tanksy]

2 minutes ago, mcarroll said:

I'm not sure what you're referring to in the RC link...I see that it's about analyzing pumps, but I don't see anything especially relevant to your situation...was it something specific that maybe you could quote here?

Obviously you're more experienced than me. I'm still learning the ropes.
I don't think the Sicce 0.5 or 1.0 you recommended would work for me, as they have head pressure of 1.2m and 1.5 respectively . The vertical height of my return pipe is about 80 cm + 5 elbows = 2.3 m. Does that make sense?

[mcarroll]

23 hours ago, RookieRock said:

The vertical height of my return pipe is about 80 cm + 5 elbows = 2.3 m. Does that make sense?

Hm...

 

On 5/20/2023 at 11:26 AM, RookieRock said:

If you're saying the total pumping height depicted in the diagram is only 1 meter (500+25+350=875mm as written)...

 

Then isn't total pumping length more like (500+25+350+350=) 1225mm?  AKA 1.2 meters?  Maybe as much as 1.8 meters if you count the horizontal portions of the return as +600mm?

 

I don't see how you can get up to 2.5m with the depicted layout and numbers, so at least for this example I'm sticking with 1.5 meters just to show you how I'm running the calculation and to keep the rest of the example simpler.  (The difference is insignificant...same calculator output.)

 

Remember total pumping length is what you use for calculating friction loss.  

 

The result is what you add to the total pumping height so that the number you use on the flow chart accounts for friction loss AND gravity.

 

So first convert your metric to imperial for the calculator:

• 180 L = 47 gallons; 47 GPH = .78 GPM
• 1.5 meters = 5 feet
• water will be 79ºF and 1.025 s.g.

Using these fittings:

• 1/2" pipe size
• 10 standard (short) 90º elbows
• 1 flow-through Tee

 

With those inputs, the calculator says you'll have an additional +0.1 feet of head loss from friction.

Liquid Friction Pressure Loss
Pressure Loss (psi):  0.05   Head Loss (ft):  0.1
Line Number:    Date:  5/22/2023 Nominal Pipe Size:  0.5 Pipe Schedule:  SCH 40  Flow Rate (gpm):  0.78 Viscosity (cP):  1 Specific Gravity (water=1):  1.025 Temperature (F):  79 Pipe Roughness (ft):  0.000016 Actual Pipe ID (in.):  0.622 Fluid Velocity (ft/sec):  0.82 Reynolds Number:  4065 Flow Region:  Turbulent Friction Factor:  0.04 Overall K:  9.8	Piping Length (ft):   5 Short Radius Elbows:  10 Tee Flow Through:  1

 

So....taking this back to metric and your pump...

 

0.1 feet = 0.03 meters

 

1 meters (gravity) + 0.03 meters (friction) = 1.03 meters of total head loss is what you take to the Sicce (or other) flow chart.

 

To get 180 l/h at 1.03 meters, a "0.5" or "1.0" model is all it would take.

 

"0.5" – 1x under your target, but fine given the usual "2x-4x" rule of thumb

"1.0" – 9x of overkill

 

BTW, if you re-run the calculation with the same parameters but upgrade from 1/2" to 3/4" pipe size, then for practical purposes the friction losses disappear:

Liquid Friction Pressure Loss
Pressure Loss (psi):  0.01   Head Loss (ft):  0
Line Number:    Date:  5/22/2023 Nominal Pipe Size:  0.75 Pipe Schedule:  SCH 40  Flow Rate (gpm):  0.78 Viscosity (cP):  1 Specific Gravity (water=1):  1.025 Temperature (F):  79 Pipe Roughness (ft):  0.000016 Actual Pipe ID (in.):  0.824 Fluid Velocity (ft/sec):  0.47 Reynolds Number:  3069 Flow Region:  Critical Zone, Results are Suspect Friction Factor:  0.043 Overall K:  8.66	Piping Length (ft):   5 Short Radius Elbows:  10 Tee Flow Through:  1

 

Hopefully it's more clear how the calculator works if you still think I have the length numbers off....you can re-run the calculations.  

 

It might be interesting to model the differences between Tee's and Wye's like I did 90º's vs 45º's earlier too.

 

[MLS_Reef]

just to chime in, is it typical to have all of the unions? Usually the more unions the lower the flow, i'm not sure if you are going for decorative pipe, i never did, pipe is cheap and i agree with reefkid88 use 45's normally i would not use a union except for next to a pump to be able to remove it.

 

[MLS_Reef]

On 5/20/2023 at 11:26 AM, RookieRock said:

Hi all, 

After a hectic year, I'm finally able to start setting up my nano reef tank.
I'm looking for the right size of pump. But I'm a bit confused. Here's a quick sketch of the plumbing.
 

 

As you can see, the return pipe splits in two, so that I can have two return nozzles.
How can I calculate the head pressure and if I want to have a 3x turnover, what flow rate should the return pump have?
The gross volume of the tank is about 60 l.

Cheers!

Also as i finish reading the thread i have used a jebao dcp 4000 on a 29 gallon with a 10 gallon sump, the overflow was a glass holes box with 1.5 inch drain and 2 - 3/4" returns 

 i ran that pump from half power.  

[Tanksy]

11 hours ago, MLS_Reef said:

Also as i finish reading the thread i have used a jebao dcp 4000 on a 29 gallon with a 10 gallon sump, the overflow was a glass holes box with 1.5 inch drain and 2 - 3/4" returns 

 i ran that pump from half power.  

Yes, I plan to throttle the VAP-2500 down.