PVC pipe dimensions - did I just screw up?!

kilnakorr

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Hi

I just finished glueing most of the piping for my tank.
However, I just noticed the way you US people are dimensioning pipes are different from where I live.

So, I thought I was using close to 1" pipes, but inner diameter is actually just a bit more than 3/4".

Looking for a 3-5x turnover in my 90 gl tank.

So, I'm I ok with my piping?
 
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spfahnestock

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There are many smarter than me on this topic but...

I believe turnover for the tank is also based on the return pump selected. If the return pump you selected is not capable of meeting that turnover rate based on distance from the pump to the return nozzle I am not sure that the ID (Inner Diameter) of the pipe will matter.

However with the correct pump will most likely be able to meet the turn over rate with a 3/4 in ID return pipe.

On a side not i believe that an outer diameter pipe of 1 in will have an inner diameter of 3/4 in.
 

Stigigemla

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Yes. If the tubes are short and without a lot of elbows it should work.
I get about 2000 liters per hour from a vertical 25mm pipe.
 
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kilnakorr

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On a side not i believe that an outer diameter pipe of 1 in will have an inner diameter of 3/4 in.
Yes. Seems that US 1" pipe are INNER diameter. However, here inner diameter is not listed only outer diameter ( so same size piping have different diameter based on fitting?!) A 25 mm(1") pipe is 21mm internal, but 25mm hosetail is just 16 mm internal... so confusing.

I believe turnover for the tank is also based on the return pump selected.

Easy fix with larger return pump.
 
Maxout

mfinn

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Hi

I just finished glueing most of the piping for my tank.
However, I just noticed the way you US people are dimensioning pipes are different from where I live.

So, I thought I was using close to 1" pipes, but inner diameter is actually just a bit more than 3/4".

Looking for a 3-5x turnover in my 90 gl tank.

So, I'm I ok with my piping?
What specifically did you use for drains( how many) and return?
 

mfinn

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As long as you aren't looking for a huge amount of flow, you should be fine.
Good luck getting a ball valve to adjust.
I'd keep looking for something with a finer tuning ability.
Something has to be available. Find a plumbing store, or whatever is the equivalent in Denmark.
 

Soren

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Yes. Seems that US 1" pipe are INNER diameter. However, here inner diameter is not listed only outer diameter ( so same size piping have different diameter based on fitting?!) A 25 mm(1") pipe is 21mm internal, but 25mm hosetail is just 16 mm internal... so confusing.



Easy fix with larger return pump.
The reason that pipes are named by internal diameter is that this is the most critical dimension when considering flow, especially for common PVC pipe. There are different "Schedules" for wall thickness to deal with different pressure ratings. Most common are Schedule 40 for typical pressure and Schedule 80 for higher pressure. Outer diameter will be about the same for the same nominal dimension.
 

Dabcrusher

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There are many smarter than me on this topic but...

I believe turnover for the tank is also based on the return pump selected. If the return pump you selected is not capable of meeting that turnover rate based on distance from the pump to the return nozzle I am not sure that the ID (Inner Diameter) of the pipe will matter.

However with the correct pump will most likely be able to meet the turn over rate with a 3/4 in ID return pipe.

On a side not i believe that an outer diameter pipe of 1 in will have an inner diameter of 3/4 in.
It all depends on your return pump gallon per hour id say it would have to be at least 1200gph
 
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kilnakorr

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Good luck getting a ball valve to adjust.
I'd keep looking for something with a finer tuning ability.
Something has to be available. Find a plumbing store, or whatever is the equivalent in Denmark.
Looked everywhere, and local forums etc. shows same issue.
Even marine and reef stores don't sell these.

Think I'll look for a gate valve on amazon or ebay...

It all depends on your return pump gallon per hour id say it would have to be at least 1200gph

Current pump is 1800 - 2300 g/h so should be enough. I might get another one, but want to run a test first.

The reason that pipes are named by internal diameter is that this is the most critical dimension when considering flow, especially for common PVC pipe

Exactly! Which is why I got confused since obviously the inner diameter is not the common way to list things.
My hose tails is listed (and marked on the fitting itself) as 25 / 28 - 25mm. However, inner diameter is just 16 mm.
 

Soren

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Exactly! Which is why I got confused since obviously the inner diameter is not the common way to list things.
My hose tails is listed (and marked on the fitting itself) as 25 / 28 - 25mm. However, inner diameter is just 16 mm.
I still find it a bit confusing, since I was under the impression that the inner diameter was true to dimension while the outer diameter increased for higher pressures and thicker walls. While checking dimensions for my earlier response, I noticed that the PVC Schedules have the same outer diameter while the inner diameter gets slightly smaller with the thicker walls of Schedule 80 pipe.

I guess the answer is to always confirm the specific dimensions of each item and make sure they match other plumbing parts.
 

Saltyreef

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The reason that pipes are named by internal diameter is that this is the most critical dimension when considering flow, especially for common PVC pipe. There are different "Schedules" for wall thickness to deal with different pressure ratings. Most common are Schedule 40 for typical pressure and Schedule 80 for higher pressure. Outer diameter will be about the same for the same nominal dimension.
Well stated :)
Schedule 80 fittings and schedule 40 pipe is what most people use due to the smaller ID of sch. 80 pipe.
Plus everyone loves the grey fittings lol.
 

Soren

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Well stated :)
Schedule 80 fittings and schedule 40 pipe is what most people use due to the smaller ID of sch. 80 pipe.
Plus everyone loves the grey fittings lol.
Yes, I may use all schedule 80 for my plumbing since it is dark gray. The color coding is definitely helpful in making sure the dimensions match between different components.
 
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kilnakorr

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I guess the answer is to always confirm the specific dimensions of each item and make sure they match other plumbing parts.
True. But when you have to order online and the only thing listed is 'bend - 25 mm' it gets difficult.
Hardware stores don't have this stuff so you have to buy from expensive aquarium hobby stores - spend close to $200 for my build.
 
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Soren

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True. But when you have to order online and the only thing listed is 'bend - 25 mm' it gets difficult.
Hardware stores don't have this stuff so you have to buy from expensive aquarium hobby stores - spend close to $200 for my build.
I can understand your difficulty as you describe, though I cannot relate, since I can walk into a hardware store in the USA and browse a large selection of plumbing items in person and can even measure dimensions myself to confirm.

I would recommend that you check with suppliers on dimensions before ordering, though this makes it much more challenging when the information is not just given to begin with. This is precisely why there are standards developed, such as pipe schedules, so all information is able to be confirmed from just the nominal dimension and schedule.
 

Johniejumbo

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Pipes have so many different measurements. Tubing is in a class of its own and can be very confusing because of all the different types. Definitely need to confirm dimensions for compatibility. Pvc isn’t as bad as tubing but still confusing. Most pvc uses iron pipe size outside diameter so it can connect with the galvanized fittings and iron pipe threads and such. There is copper tube size pvc as well (cpvc) so make sure you don’t accidentally get that stuff. It won’t work with sch 40 and 80. Amazon here in the US sells Spears pvc fitting including pvc gate valves. Not certain if they reach over there though.
 
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kilnakorr

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I would recommend that you check with suppliers on dimensions before ordering, though this makes it much more challenging when the information is not just given to begin with.
Lesson learned. I was stupid to get the idea that that 25mm pipe wasn't 25mm internal.
However, the hosetail fits perfectly together with the rest of the fittings, but walls are thicker, hence the smaller inner diameter.
What frustrates me is the stores pretty much only has this one type.

Amazon here in the US sells Spears pvc fitting including pvc gate valves. Not certain if they reach over there though.
Problem with ordering from US is taxes. $25 flat fee plus 20% taxes on item.

Anyway, as long as I can get my roughly 500 g/h through 3/4" I'm good.
Hosetails are only used through UV which is branched of the return, and I don't need that much flow through the UV.
If everything fails, I can split the return and run the UV to the tank. This will get me 2 x 3/4".
However, I can't make the drain pipe larger as holes won't allow larger pipes.
 

DCR

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You should be fine with nominal 1" pipe for a 90 gal. We take the actual ID into account when making the pipe size recommendations. The reason OD is standardized is so that any Schedle pipe will fit in any socket welded fitting (i.e. you can use Sch 80 socket welded fittings with Sch 40 pipe).
 
Maxout

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