GPH with 3/4" return to tank

[Thor2j]

I am awaiting delivery of my innovative marine 200 int peninsula. Strangely it only has a 3/4" return that tees off to 2 3/4" into aquarium. IM recommends 2000-4000 gph on their website for tank. First off , I'm a fan of 3-4x tank turnover so with sump somewhere around 900 gph. Can you even get that through a 3/4" pipe?? I asked IM and they were kind of stumped.

 

[Reefer Reboot]

Depends on pressure. Check this website, https://flexpvc.com/Reference/WaterFlowBasedOnPipeSize.shtml

 

[theMeat]

I am awaiting delivery of my innovative marine 200 int peninsula. Strangely it only has a 3/4" return that tees off to 2 3/4" into aquarium. IM recommends 2000-4000 gph on their website for tank. First off , I'm a fan of 3-4x tank turnover so with sump somewhere around 900 gph. Can you even get that through a 3/4" pipe?? I asked IM and they were kind of stumped.

You’ll be fine. Elbows restrict less when water is under pressure as well. Good idea to run at least a short piece of tubing off pump before you transition to rigid pvc to isolate pump vibration

 

[t5Nitro]

I run a varios 4 on my EXT 75, same plumbing that yours will have. Not sure what the head loss is.

 

[Thor2j]

Depends on pressure. Check this website, https://flexpvc.com/Reference/WaterFlowBasedOnPipeSize.shtml

I've seen that chart before but what pressure does a marine aquarium pump run at, 3???

 

[Thor2j]

I run a varios 4 on my EXT 75, same plumbing that yours will have. Not sure what the head loss is.

Don't care about the head loss, have plenty of pump, it's about the max gph flow you can get out of 3/4" pvc?? Plis I have 3x your water volume

 

[t5Nitro]

Your original question asked if you can get 900 gph through 3/4" pipe. The answer is yes. The assumption on your most recent post above is that you want a flow rate much higher than that. Maybe more can chime in.

 

[Reefer Reboot]

The PSI is developed by your head pressure unless you were to close off the return. Closing off the return would be the same as the maximum head pressure. Maximum head pressure should be listed in the data sheet for whichever pump you are using. Which pump are you using? What is the vertical heigth that you are pumping up to your DT?

 

[theMeat]

The pressure and gph your pump puts out works against the head pressure. As an example if your pumps output is 1400 gph at 20 psi with zero head pressure, both gph and psi decrease as head pressure increases, until both #s reach zero which is it’s max head pressure.
Op, the simple answer is yes, 3/4 pipe would put you comfortably in the 900 to 1000 gph your looking for. Here’s a link to help you figure the math if you think the tank manufacturer knows less than you.

An Engineering View Of Aquarium Systems Design: Pumps And Plumbing

This article presents an engineering view of plumping and plumbing system design for reef aquariums, and provides a basis for evaluating plumbing designs and selecting pumps.

reefs.com

 

[Reefer Reboot]

both gph and psi decrease as head pressure increases, until both #s reach zero which is it’s max head pressure.

IDK, I just found that this part of your statement could be a little confusing to those who may not quite understand hydraulic principles.
So, just a little clarification. Regarding the psi, this is only true if you are measuring the psi at the very top of the water level at maximum head.
Another way of looking at it, let's imagine a pump which goes straight into a vertical pipe, and that pipe extends higher than the maximum head. With the pump running, if you were to measure the psi at the pump outlet (bottom of the pipe) it will increase as the head pressure (aka water level) increases. If you were to measure the psi at the very top of the water level, there it will be zero. This difference in pressure is due to the weight of the water.
Hope you don't mind the clarification.

 

[theMeat]

IDK, I just found that this part of your statement could be a little confusing to those who may not quite understand hydraulic principles.
So, just a little clarification. Regarding the psi, this is only true if you are measuring the psi at the very top of the water level at maximum head.
Another way of looking at it, let's imagine a pump which goes straight into a vertical pipe, and that pipe extends higher than the maximum head. With the pump running, if you were to measure the psi at the pump outlet (bottom of the pipe) it will increase as the head pressure (aka water level) increases. If you were to measure the psi at the very top of the water level, there it will be zero. This difference in pressure is due to the weight of the water.
Hope you don't mind the clarification.

Don’t mind at all, and not looking to bicker or take over op’s thread, but no. The psi doesn’t increase at pump with added head height. I understand what you’re trying to say, tho.
Let‘s put it this way. As you increase the head height it puts more psi against the pipe. If you reach max head height you have max pressure against the pipe at pump output because that’s the lowest point with most water pushing down (gravity). But if the pipe has an outlet or is not over max head height the psi goes out of pipe instead of pushing against pipe. Path of least resistance. Gph (viscosity) is directly related to psi of output, minus head height. Either way a moot point since output is the concern and just confuses things more, imo. But an interesting point, thanx for adding to the convo

 

[Reefer Reboot]

I've seen that chart before but what pressure does a marine aquarium pump run at, 3???

Just trying to help OP get the answer they are looking for. Thank you for your input.

 

[Logical_Plan]

I would be careful thinking you have plenty of pump.

Say you are using a vectra L2, here is the pump curve:

Now assume 3/4 inch PVC and desired flow of 900 gph or 15 gpm. Assuming efficient plumbing 4' vertical height and 10' overall length ( 4' vertical, 6' horizontal), 2-45 elbows and one 90 into the tank. All 3/4" PVC.

Using this head calculator:

Pump Calculator | Pentair AES

Pentair is dedicated to excellence in all aspects of our business. Whether you need system design, technical service or unrivaled equipment-you can count on us.

pentairaes.com

Gives you 10.23 feet of head. Looking at the pump curve your max gph at that head is around 1500 gph or slightly more than 1/2 of what you were expecting.

Say you try and run 1500 gph in that same 3/4" plumbing (25 gpm). Total head of the plumbing is now 20.43 feet. You can't run that much. Flow will top out at something less than that.

Same example running a 1-1/4" PVC plumbing instead of 3/4". At 900 gph, 15 gpm, you are now only at 4.5 feet of head, max flow from pump is now 2500ish gpm.

What happens if we try to push 2500 gpm, 41.67 gpm in that same 1-1/4" pipe? 7.98 feet of head. So likely 2100 or 2200 gph max once you figure out exactly where the system curve ( total head loss from pentaire calculator) intersects the pump curve.

TLDR;. A single 3/4" return seems small.

 

[AJsReef]

+1 on above, I wouldn’t be confident on pumps abilities.

Anecdotal experience here; I have a 750XXL so similar display size. My return plumbing is 1”, ~5’ of physical head pressure and 4 elbows in my plumbing. I’ve tried several well made pumps rated around 2,750GPH (Varios-8, Red Dragon 150w) and 550GPH was my max observed flow.

I would venture to say, it would be noticeably less with 3/4” return line.

 

[Logical_Plan]

+1 on above, I wouldn’t be confident on pumps abilities.

Anecdotal experience here; I have a 750XXL so similar display size. My return plumbing is 1”, ~5’ of physical head pressure and 4 elbows in my plumbing. I’ve tried several well made pumps rated around 2,750GPH (Varios-8, Red Dragon 150w) and 550GPH was my max observed flow.

I would venture to say, it would be noticeably less with 3/4” return line.

Varios-8 has a max head of 10' or so IIRC. So that makes sense.

 

[AJsReef]

Varios-8 has a max head of 10' or so IIRC. So that makes sense.

I think they are sold at 15’+, but have my doubts there.

I’ve been on a quest to improve from the Varios Flow but even the RD was basically the same performance. Thinking I would’ve needed a 150w or Abyzz A200 to get over 550GPH (3x for my system).

I don’t have factual data to support limitations of 3/4” pipe. I do know my discussions with Alex at Abyzz pointed to even 1” causing sizable limitations in flow for most pumps. Many of these higher flow pumps are plumbed with 1-1/4” (or larger) outflow for a reason

 

[Logical_Plan]

I think they are sold at 15’+, but have my doubts there.

I’ve been on a quest to improve from the Varios Flow but even the RD was basically the same performance. Thinking I would’ve needed a 150w or Abyzz A200 to get over 550GPH (3x for my system).

I don’t have factual data to support limitations of 3/4” pipe. I do know my discussions with Alex at Abyzz pointed to even 1” causing sizable limitations in flow for most pumps. Many of these higher flow pumps are plumbed with 1-1/4” (or larger) outflow for a reason

Low head output is one of the main challenges of DC pumps currently. The AC pumps tend to perform better in the higher head situations.

 

[DCR]

There is no way you will get 900 gph through a 3/4" return of any length with commonly available aquarium pumps that we use. I would generally say that 350-400 gph is the most you could reasonably expect, regardless of what pump you have. The green column in that table is the only one that is applicable to an aquarium application and even that is a maximum flow rate. The yellow column is for 20-100 psi of head loss which is equal to 46-230 ft of head. You would need a pump that would put up that much head at the flow rate that you want (not the zero flow head). That is a spa or industrial pump.

 

[outhouse]

Those numbers insane, 900 way to much. with a 210g display and 100g sump, I run between 200-700 between 2 X 3/4 returns.

It will do it, but freaken why is the question, it makes the drain way to noisy, I like a quiet tank, or just a small stream sound if its dead silent

 

[outhouse]

There is no way you will get 900 gph through a 3/4" return of any length with commonly available aquarium pumps that we use. I would generally say that 350-400 gph is the most you could reasonably expect, regardless of what pump you have. The green column in that table is the only one that is applicable to an aquarium application and even that is a maximum flow rate. The yellow column is for 20-100 psi of head loss which is equal to 46-230 ft of head. You would need a pump that would put up that much head at the flow rate that you want (not the zero flow head). That is a spa or industrial pump.

No lol my old iwaki would put 900 through it all day long! of wait its industrial grade lol my Jebao would do it all day long as well.

Your point however, is on point, thats what I run through each 3/4 return. You can do much more, but there is no reason. The weak spot is the drain anyway and the noise it makes.