calculating head pressure

[Reefrookie733]

I know there is alot of discussion about this top whether its really relevant but i would like to know if my calculations are somewhat correct???

3 elbows = 3 ft
1 tee = 1 ft
10 feet of pvc = 1 ft.
1 split (essentially tee) = 1 ft

THEN reduce from 1.5 pvc to 3/4 = any loss there?
with 2 x 3/4 elbows going into tank = 2 ft. ??

Thinking total is 8 feet of head pressure??

thx

 

[Super Fly]

here's the data I used to calc my system's pressure loss, I just took the "avg loss" value when using in formula, i.e. 75 to 125 GPH loss avgs to 100.

A loss of 75 to 125 GPH for each foot of height (from the pump to the display tank return)

A loss of 50 to 75 GPH for each 90 degree elbow

• A loss of 30 to 50 GPH for each 45 degree elbow

• A loss of 50 to 75 GPH for each swing check valve

• A loss of 20 to 40 GPH for each ball valve

• A loss of ~ 3 to 5 GPH for each union

 

[Reefrookie733]

here's the data I used to calc my system's pressure loss, I just took the "avg loss" value when using in formula, i.e. 75 to 125 GPH loss avgs to 100.

A loss of 75 to 125 GPH for each foot of height (from the pump to the display tank return)

A loss of 50 to 75 GPH for each 90 degree elbow

• A loss of 30 to 50 GPH for each 45 degree elbow

• A loss of 50 to 75 GPH for each swing check valve

• A loss of 20 to 40 GPH for each ball valve

• A loss of ~ 3 to 5 GPH for each union

That's too much math for me! lol

 

[JoshH]

Use this calculator (Linked Below) to calculate the total friction loss of your pipe then add that to the total height the plumbing has to rise (from the actual water level in your sump to the height of the outlet in your display and not the height from the top of the pump) and you have what's called TDH or Total Dynamic Head pressure. This is the number you'll need to work with when selecting the appropriate pump for the flow you want...

On-Line Friction Piping Loss

 

[Reefrookie733]

Use this calculator (Linked Below) to calculate the total friction loss of your pipe then add that to the total height the plumbing has to rise (from the actual water level in your sump to the height of the outlet in your display and not the height from the top of the pump) and you have what's called TDH or Total Dynamic Head pressure. This is the number you'll need to work with when selecting the appropriate pump for the flow you want...

On-Line Friction Piping Loss

Thank you

 

[Reefrookie733]

Thank you

lol....really sorry i dont have a math degree. But i did stay in a holiday inn one time! lol

I tried to plug in what variables i could and it gave me INFINITY! lol

 

[Reefrookie733]

Liquid Friction Pressure Loss​
Pressure Loss (psi): Infinity Head Loss (ft): Infinity
Line Number: Date: 4/28/2020 Nominal Pipe Size: 1.5 Pipe Schedule: SCH 40 Flow Rate (gpm): 43 Viscosity (cP): 1 Specific Gravity (water=1): 1 Temperature (F): 70 Pipe Roughness (ft): 0.000016 Actual Pipe ID (in.): 1.61 Fluid Velocity (ft/sec): 6.78 Reynolds Number: 84467 Flow Region: Turbulent Friction Factor: 0.019 Overall K: Infinity	Piping Length (ft): 10 Long Radius Elbows: 5 Tee Flow Through: 2 Swing Check: 1	Ball : 2 No. of Reducers: 2

 

[JoshH]

Did you put a project name in the very top input?

Also you want 2600 GPH of flow from your returns?

 

[JoshH]

So looking at 40 GPM rating this is what I've come up with

So you're looking at 4.8Ft of friction loss, add that to the height of your plumbing rise and you'll be really close to what you need to know.

 

[Reefrookie733]

So looking at 40 GPM rating this is what I've come up with

So you're looking at 4.8Ft of friction loss, add that to the height of your plumbing rise and you'll be really close to what you need to know.

So i have about 6 feet of rise. do i add that to the friction loss to get my total head pressure??

 

[JoshH]

So i have about 6 feet of rise. do i add that to the friction loss to get my total head pressure??

Yup, exactly, so you are looking at about 11Ft give or take of head height. Important to remember this is at 2400GPH flow rate, not sure if that is your goal for flow on your return but it seems a little on the higher side of things.

 

[Reefrookie733]

Yup, exactly, so you are looking at about 11Ft give or take of head height. Important to remember this is at 2400GPH flow rate, not sure if that is your goal for flow on your return but it seems a little on the higher side of things.

well right now i have a reeflo superdart gold and it will run up to 4200 GPH according to its website, but i have it throtteld back to about 60% of max so i would not expect that type of flow.

 

[Reefrookie733]

Yup, exactly, so you are looking at about 11Ft give or take of head height. Important to remember this is at 2400GPH flow rate, not sure if that is your goal for flow on your return but it seems a little on the higher side of things.

This is why this is so important for a 200G DT i am trying to figure out can i get away with a 2000 GPH pump like the vectra M2 or do i need the higher rate like the Varios 8 at 2700 GPH or all the way to Vectra L2 at 3100 GPH ??/

 

[JoshH]

I would say at those flow rates your probably going to have to step into something a little scarier on the budget side of things.

 

[Reefrookie733]

I would say at those flow rates your probably going to have to step into something a little scarier on the budget side of things.

I think i want to poll the forums to find out what is the average (good) size return pump for a 200G DT and 75G sump

thanks

 

[DCR]

I am not sure how the program treated those two 3/4" returns, but I don't think they are going to support 40 gpm without an extremely high head loss. It would be an incredible jet stream coming out of them if you did.

 

[rob myers]

I have a reef octopus water. Blaster 5000 running two three quarter return lines with two equaductors on each line ran one inch as high. As I could and then reduced to 3/4 have a valve on each line and then adjusted pressure has no problem feeding tank at 5 ft . 220 gal with 75 gal sump.

 

[rob myers]

This pump is 1300 gal per hour

 

[rob myers]

Same pump on my three hundred gallon also

 

[Reefrookie733]

D

Same pump on my three hundred gallon also

rob, do you have a lot of power heads in those 2 tanks as well??