How much elbows cut flow....? Swapping sumps..

[Fin]

If you do consider the flex PVC, I have used this stuff from Glass-Holes. It is more flexible than the Spa flex. They only carry 1" / 1½" / 2" now. I have used the ½", 3/4" & 1" in the past and found it much easier to manage than the stuff you get at Lowe's or HD.

 

[TheEngineer]

@Fin found and posted the video...i guess i didn't recall the video very well. It is testing flow reduction difference between using 90 degree elbows vs 2 45 degree elbows. Interesting though, shoes minimal differences in reduction from the stated gph in the pump for lower gph pumps but greater reduction from higher gph pumps! I guess maybe their is some sort of turbulence or something creating loss at higher pressures and not letting the pump fiction at maximum efficiency. But, the video does show that the lower gph pumps really didn't show much reduction in pressure compared to their advertised output with the 90 degree elbows... but the higher goh pumps did.

Friction increases with force. Makes sense it would be worse at pressure.

 

[ShawnSaucier]

If you do consider the flex PVC, I have used this stuff from Glass-Holes. It is more flexible than the Spa flex. They only carry 1" / 1½" / 2" now. I have used the ½", 3/4" & 1" in the past and found it much easier to manage than the stuff you get at Lowe's or HD.

Yeah, I may have to order some of this. Also just bump the pump back to the L1, flex pvc to the bulkhead, change the 90 a the top of the sump to a 45 and use the flex pvc after the Union on the FMK module to the tank bulkhead.

 

[DCR]

I have worked as an engineer with fluid flow for over 35 years. It is not practical to get 1700 gph through 1" piping, no matter what you do with elbows and fittings. You would probably need a pump with over 100 ft of head to acheive 1700 gph through 1" Sch 80 piping. The elbows do add additional head loss (generally equivalent to 30 pipe diameters of straight run), but you are not going to see any substantial increase by replacing them. You would need to upgrade the return piping to at least 1-1/2" to achieve 1700 gph with most aquarium pumps.

Everyone quotes these zero head max output values of their pumps - but they are meaningless. You really need to be looking at how much flow a pump puts out at 7-8 ft of head assuming you have sized your lines appropriately. For example, an M1 is rated for 2000 gph at zero head, but only puts out about 1000 gph at 8 ft.

I would generally recommend going with 3/4" up to 300 gph, 1" up to 600 gph, 1-1/4" up to 1200 gph, 1-1/2" up to 1800 gph and 2" up to 3000 gph. These are for Sch 40 as well. Using Sch 80 reduces the flow further. If you do that and select a pump that provides your desired flow rate at about 6-8 ft of head you should be close.

Attached is a link to head losses in PVC Sch 40 piping. In industrial practice, we would generally size lines for about 5 ft of head loss per 100 ft of equivalent piping. Fittings and exit losses are generally converted to equivalent straight run piping to determine the pressure loss. It is very easy to get to 50 ft of equivalent piping in a simple aquarium system. You then have to add the elevation differenece beween your tank level and return pump chamber level to get the total head requirement for the pump.

https://www.engineeringtoolbox.com/pressure-loss-plastic-pipes-d_404.html

 

[ShawnSaucier]

I have worked as an engineer with fluid flow for over 35 years. It is not practical to get 1700 gph through 1" piping, no matter what you do with elbows and fittings. You would probably need a pump with over 100 ft of head to acheive 1700 gph through 1" Sch 80 piping. The elbows do add additional head loss (generally equivalent to 30 pipe diameters of straight run), but you are not going to see any substantial increase by replacing them. You would need to upgrade the return piping to at least 1-1/2" to achieve 1700 gph with most aquarium pumps.

Everyone quotes these zero head max output values of their pumps - but they are meaningless. You really need to be looking at how much flow a pump puts out at 7-8 ft of head assuming you have sized your lines appropriately. For example, an M1 is rated for 2000 gph at zero head, but only puts out about 1000 gph at 8 ft.

I would generally recommend going with 3/4" up to 300 gph, 1" up to 600 gph, 1-1/4" up to 1200 gph, 1-1/2" up to 1800 gph and 2" up to 3000 gph. These are for Sch 40 as well. Using Sch 80 reduces the flow further. If you do that and select a pump that provides your desired flow rate at about 6-8 ft of head you should be close.

Attached is a link to head losses in PVC Sch 40 piping. In industrial practice, we would generally size lines for about 5 ft of head loss per 100 ft of equivalent piping. Fittings and exit losses are generally converted to equivalent straight run piping to determine the pressure loss. It is very easy to get to 50 ft of equivalent piping in a simple aquarium system. You then have to add the elevation differenece beween your tank level and return pump chamber level to get the total head requirement for the pump.

https://www.engineeringtoolbox.com/pressure-loss-plastic-pipes-d_404.html

I guess I find this shocking as all of the bulkheads on my tank are 1” and from what I understand is you want at least 10x turnover rate to the sump.

 

[ShawnSaucier]

I have worked as an engineer with fluid flow for over 35 years. It is not practical to get 1700 gph through 1" piping, no matter what you do with elbows and fittings. You would probably need a pump with over 100 ft of head to acheive 1700 gph through 1" Sch 80 piping. The elbows do add additional head loss (generally equivalent to 30 pipe diameters of straight run), but you are not going to see any substantial increase by replacing them. You would need to upgrade the return piping to at least 1-1/2" to achieve 1700 gph with most aquarium pumps.

Everyone quotes these zero head max output values of their pumps - but they are meaningless. You really need to be looking at how much flow a pump puts out at 7-8 ft of head assuming you have sized your lines appropriately. For example, an M1 is rated for 2000 gph at zero head, but only puts out about 1000 gph at 8 ft.

I would generally recommend going with 3/4" up to 300 gph, 1" up to 600 gph, 1-1/4" up to 1200 gph, 1-1/2" up to 1800 gph and 2" up to 3000 gph. These are for Sch 40 as well. Using Sch 80 reduces the flow further. If you do that and select a pump that provides your desired flow rate at about 6-8 ft of head you should be close.

Attached is a link to head losses in PVC Sch 40 piping. In industrial practice, we would generally size lines for about 5 ft of head loss per 100 ft of equivalent piping. Fittings and exit losses are generally converted to equivalent straight run piping to determine the pressure loss. It is very easy to get to 50 ft of equivalent piping in a simple aquarium system. You then have to add the elevation differenece beween your tank level and return pump chamber level to get the total head requirement for the pump.

https://www.engineeringtoolbox.com/pressure-loss-plastic-pipes-d_404.html

So essentially I should run an external return line, as my pre drilled tank that was made by a reputable custom shop, is not drilled properly for reefing needs?

 

[ShawnSaucier]

I apologize if that read rudely. Not my intention at all and I appreciate any knowledge anyone is willing to share.
I guess it’s more the thought that I paid $$$$ for something that is inadequate for the purpose it was built for

 

[DCR]

I am not sure that 700 gph is really inadequate. I think there a plenty of people that are successful at 3-5X provided they have good internal circulation in the tank. I am not a reef expert but I find it hard to believe that you really need to turn over your entire tank every 6 minutes as Triton recommends. That is a lot of flow on most tanks and I find it hard to believe that it is necessary. To put it in perspective, 1700 gph is filling a 5 gal bucket every 10 seconds. Many overflow systems will struggle with that much flow as well. I do not think many reefers come close to achieving that type of number. Most just assume that they are getting the "rated" flow of the pump they bought. The published zero head rated flows are deliberately misleading since no one buys a pump for zero head.

If you have multiple 1" bulkheads you might be able to double or triple up on them to get the flow you are looking for (with the larger diameter header). I doubt that you would really want to return 1700 gph to a single point anyway due to the turbulence and potential splashing. Otherwise your only alternative is to go over the rim. I would still recommend 2-3 retun points to avoid excessive turbulence.