• For a Limited Time the R2R Partner Membership is NOW OPEN! Get some cool swag and chances to win part of over $20,000 in prizes! Click here for more details

Why is there a common trend to grossly oversize return pumps on a new build.

OP
Palegic

Palegic

Active Member
View Badges
Joined
Jul 20, 2020
Messages
124
Reaction score
114
Location
Long Island
2x what, sump or system?
OP's first post stated "10x sump turnover rule is archaic".
To Clarify: 2x return. Talking about return pumps. 2x return through the sump.

There are recommendations out there that mention using the return (located in the sump) to turnover the water 10x. Which is an archaic rule from back when power heads were large unsightly and gave relatively little water movement compared to size and power consumption. Its 2020 some "rules" need adjusting. Just like computers equipment is out dated in a year or two.
 

EMeyer

Valuable Member
View Badges
Joined
Jan 23, 2016
Messages
1,034
Reaction score
1,545
Only thing in my sump is live rock and macro. More flow only increases the efficiency with which they process waste.

I don't doubt for a second that there are people running successful systems with very low flow through the sump. I don't think there's any benefit to doing so, and havent seen any evidence it helps (or good theoretical arguments why it should).
 

ca1ore

10K Club member
View Badges
Joined
Oct 28, 2014
Messages
11,555
Reaction score
15,828
Location
Stamford, CT
pumps capable of 2500 gph in 100g and smaller tanks.
Also keep in mind that a DC pump, particularly, will lose a significant amount of its theoretical flow in a real world application. So your 2,500 pump may only actually be doing half that.
 
OP
Palegic

Palegic

Active Member
View Badges
Joined
Jul 20, 2020
Messages
124
Reaction score
114
Location
Long Island
So far I
20%? nowhere close!
Okay well without getting into theoretical figures because neither one of us guaranteed have the data to back it up for a multitude of pumps. I can agree that 20% may not be enough to cover loss through the system as that number is way low, but 2500% is clearly too much.
 
Fragtacular Sale
OP
Palegic

Palegic

Active Member
View Badges
Joined
Jul 20, 2020
Messages
124
Reaction score
114
Location
Long Island
Also keep in mind that a DC pump, particularly, will lose a significant amount of its theoretical flow in a real world application. So your 2,500 pump may only actually be doing half that.
This is an answer. Thank you for not getting defensive about justifying your large return pump and high return pump turnover rate.
 

WVNed

The fish are staring at me with hungry eyes.
View Badges
Joined
Apr 11, 2018
Messages
5,318
Reaction score
20,402
Location
Hurricane, WV
Also keep in mind that a DC pump, particularly, will lose a significant amount of its theoretical flow in a real world application. So your 2,500 pump may only actually be doing half that.
Or 1/4th even. I have 2 x 2000gph pumps on a 400 gallon system but I measured my flow using the bucket/stopwatch method. I am getting 1000ghph.
That is with a head height of only about 2 feet too.
 

BZOFIQ

Valuable Member
View Badges
Joined
Jul 31, 2014
Messages
1,997
Reaction score
1,747
Location
NYC
Here is a fairly popular DC pump on the market. Look at the chart, take height of the stand, add height of the tank and then few feet of loss due to elbows and you end up with about 8ft of height which would give you about 1300 GPH (50% plus loss).

Change its ouput down from 1.25" piping to 1" and/or add a manifold and you'll be lucky to get 800 GPH.

Quite a bit more than 20% loss

With these numbers a 125-180 Gallon tank would have 5-6x flow - not more.

1597348944951.png
 
OP
Palegic

Palegic

Active Member
View Badges
Joined
Jul 20, 2020
Messages
124
Reaction score
114
Location
Long Island
Here is a fairly popular DC pump on the market. Look at the chart, take height of the stand, add height of the tank and then few feet of loss due to elbows and you end up with about 8ft of height which would give you about 1300 GPH (50% plus loss).

Change its ouput down from 1.25" piping to 1" and/or add a manifold and you'll be lucky to get 800 GPH.

Quite a bit more than 20% loss

With these numbers a 125-180 Gallon tank would have 5-6x flow - not more.

1597348944951.png
Thanks! Good info
 

BZOFIQ

Valuable Member
View Badges
Joined
Jul 31, 2014
Messages
1,997
Reaction score
1,747
Location
NYC
Thats a good answer. Figuratively speaking running a 2500gph pump on a 100g system at 30% is still 7.5x an probably 3 times what is actually needed.
@Palegic

You keep quoting 20-30% loss when I've shown you that the loss is somewhere in the 50-70% range.

Even @WVNed is showing you an actual loss of 75% on his dual pump setup.
 
OP
Palegic

Palegic

Active Member
View Badges
Joined
Jul 20, 2020
Messages
124
Reaction score
114
Location
Long Island
@Palegic

You keep quoting 20-30% loss when I've shown you that the loss is somewhere in the 50-70% range.

Even @WVNed is showing you an actual loss of 75% on his dual pump setup.
Hey I am not quoting a 20-30% loss @BZOFIQ. Per my post I was quoting @amoore311 regarding running a DC pump @30%. Actually in a previous post I am quite receptive to understanding the loss is realistically much more than 30%
 
OP
Palegic

Palegic

Active Member
View Badges
Joined
Jul 20, 2020
Messages
124
Reaction score
114
Location
Long Island
Or 1/4th even. I have 2 x 2000gph pumps on a 400 gallon system but I measured my flow using the bucket/stopwatch method. I am getting 1000ghph.
That is with a head height of only about 2 feet too.
400g is a huge system and your using two 2000gph pumps which I would consider adequate. My OP referred to those sizing their return pumps flow upwards of 25 times their system volume which would be like you using a (2) ReeFlow Hammerhead pumps or two Abyzz A400s.
 

ErehwoN

Community Member
View Badges
Joined
Jul 4, 2020
Messages
82
Reaction score
88
Location
Clatskanie OR
Because they know in their mind that they will be getting a bigger tank :)
This.... My 55 gal has a pump with the marketing stating a rate of 1900gph. I'm not running it at full capacity and it's still a bit of overkill. But as I started really understanding sumps and tank mechanics I knew my end goal is going to require a larger tank. I don't know if that's 6 months or 6 years in the future, but I know it's coming. Once that starts, I'll buy something for the 55 because it will likely be a quarantine and/or hospital tank.

Jim
 
OP
Palegic

Palegic

Active Member
View Badges
Joined
Jul 20, 2020
Messages
124
Reaction score
114
Location
Long Island
This.... My 55 gal has a pump with the marketing stating a rate of 1900gph. I'm not running it at full capacity and it's still a bit of overkill. But as I started really understanding sumps and tank mechanics I knew my end goal is going to require a larger tank. I don't know if that's 6 months or 6 years in the future, but I know it's coming. Once that starts, I'll buy something for the 55 because it will likely be a quarantine and/or hospital tank.

Jim
So if you take out the upgrade aspect and someone purchased a Red Sea 525xl (139g) Deluxe that fit their home appropriately, and asked you to recommend a return pump would you recommend they get a 5000gph return pump? or a more conservative 2000gph pump? Considering the life expectancy of the pump and likely hood that they will upgrade the tank in less than 10 years.

The real question I asked this was to indirectly understand myself as well as see how other people evaluated return pump flow. Rather than just looking a build over build and following John Smith because he has a sweet build so his return pump size must be necessary. It seems its common for people to feel that more flow through their sump = better. However, I have had discussions with some pretty well regarded folks in the industry that this just isn't always true (obviously largely dependent on setup).
 

Nburg

High-Rise Reefer
View Badges
Joined
Aug 16, 2017
Messages
1,048
Reaction score
1,131
Location
Washington, DC
I've always like the lower flow route... 4-10x, possibly more towards 4x basically to keep noise down. I see no other reason to crank up the flow through the sump.
 

Pdash

Active Member
View Badges
Joined
Mar 5, 2019
Messages
405
Reaction score
446
You lost me. Yeah, say 100 gallon system volume with a 2500gph return pump would be 25x and largely unnecessary. Your specific tank might need more or less based on specifics but 2x is more than adequate. Running a 1000gph return pump would give you more than enough adjustability.

Not exactly sure where the mention of sump volume comes into play.
No one is getting 2500gph from a 2500gph DC pump, you would be lucky to get half that on most setups in my expereince.
-(edit) oops, a few people beat me to it.
 

anit77

Active Member
View Badges
Joined
Aug 14, 2015
Messages
382
Reaction score
571
Location
Flowery Branch
You lost me. Yeah, say 100 gallon system volume with a 2500gph return pump would be 25x and largely unnecessary. Your specific tank might need more or less based on specifics but 2x is more than adequate. Running a 1000gph return pump would give you more than enough adjustability.

Not exactly sure where the mention of sump volume comes into play.
If the return pump fails then any thing else plumbed through the sump is pretty much useless anyway. If you have a few pumps to run a UV, Carbon, GFO or any other reactor when the tank water stops draining into the sump there's only so much those pieces of equipment can do until the sump water is totally stripped. That and if the pumps pull from one chamber and return to another you may risk running the pumps dry.

With a flow meter you can get a pretty good idea what your return rate to the display is. I ran a display return, manifold and a frag tank off one DCP-18000. The display and frag returns had flow meters. If the flow dropped too low I get an alert. If the pump wattage dropped too low I got an alert. Just not sure what you're looking for here.
 
Corals.com

How often do you have some type of algae issue?

  • Constantly Something

    Votes: 54 38.0%
  • Every Month

    Votes: 3 2.1%
  • Every Few Months

    Votes: 15 10.6%
  • A Few Times A Year

    Votes: 23 16.2%
  • Once A Year Or So

    Votes: 17 12.0%
  • Every Few years

    Votes: 7 4.9%
  • Never.....(are you lying?)

    Votes: 13 9.2%
  • Other (please explain)

    Votes: 10 7.0%

Online statistics

Members online
2,155
Guests online
4,246
Total visitors
6,401
MAXSPECT
Top