Return pump never outputs correct GPH according to sensor

[Mafiaboy]

Hi guys,

I'm having a hard time with this one. I have about 7 or 8 returns pump that I have tried and none of them ever work according to spec.

For example, I have a Sicce 9.0 which i can get max 1000 GPH out of it. I understand I will lose a bit GPH because of elbows and such but my sump is really not far, like almost next to the tank and shouldn't lose that much power. I also have tried multiple returns on my UV but same thing, the apex flow sensor shows only 1000gph on a return that says they can get 2600 GPH. This is literally a straight shot from my sump right into the UV.

Does pipe diameter matter here? I am still running 1 inch which if google serves me correctly should still be able to do 2000+ gph.

Some insight here would be great.

Thanks r2r

 

[KrisReef]

Pictures or a diagram of the returns?

The capacity of a pump is probably measured with zero head and calculated from a table that uses the maximum height for point 2, in other words, no one expects these pumps will ever face real scrutiny from anyone with a flow meter abd a stop watch.

Maybe you need to calibrate the flow meter?

That's all the insight I got in this matter, mostly speculation and trusting that others on here will be able to give you a real answer about your specific situation. Last thing, trivia, that an 90 elbow fitting takes out 25%(?) of flow just by inserting it into the water path? I honestly don't recall the loss% but it wasn't insignificant. Lets here what the crew knows, hopefully they have better "facts" and memory than I have on these things.

Great question, and one lousy answer!

 

[Sisterlimonpot]

DC pumps rarely measure up to what companies claim. That's marketing for ya.

Not that its an excuse but understanding that will help tamp down your expectations.

 

[Sean Clark]

First assumption: Your pump will perform as advertised. Nope.
Second assumption: Apex flow meters are accurately reporting your flow. Haha, nope.

Just set it up so your system is happy. Chasing numbers (even flow numbers) will drive you crazy. Don't over think it.

 

[FSP]

- Pipe diameter absolutely matters, you are losing a fair bit of flow to friction at 1".

- Apex sensor itself is a point of restriction, and I'd question its accuracy the same way I do other hobby grade devices. Not to say it isn't fun or interesting, but it's not a Krohne.

- The pump itself is likely off. I remember reading elsewhere that only some of the higher end German DC pump manufacturers (Abyzz, Aquabee, Deltec, RE) were close to their rated value, though I don't remember them listing the ones that don't. At those prices, you'd better get the listed flow rates

 

[Mafiaboy]

It just sucks overall because I need to know the flow to the UV, I don't really care too much about the main return.

How am I supposed to hit suggested targets of the UV if i don't have an accurate depiction of the GPH lol?

 

[Sean Clark]

It just sucks overall because I need to know the flow to the UV, I don't really care too much about the main return.

How am I supposed to hit suggested targets of the UV if i don't have an accurate depiction of the GPH lol?

The target flow rates for uv treatments are quite wide. Shoot for the middle with your flow meters and you will be fine.

 

[BaliReefBox]

a 1 litre cup and a stop watch will set your flow...you can adjust th sov to suit

 

[mdb_talon]

I am sure in some lab somewhere in some magic perfect scenario they once got the flow they advertise

As someone else pointed out though who knows how accurate your sensers are either.

If you had some very large containers you could test it yourself with a stopwatch and measuring how much in 1 minutes or something like that. Probably not reasonable with a 2600 GPH(rated) pump

 

[Tamberav]

It just sucks overall because I need to know the flow to the UV, I don't really care too much about the main return.

How am I supposed to hit suggested targets of the UV if i don't have an accurate depiction of the GPH lol?

Using your math skills.. duh

Fill a bucket to a certain number of gallons and set a stop watch.

Them apex sensors.. they got your money. when a 3 dollar bucket should be more accurate.

Edit, here I find a link for you with steps

The Many Uses For Powerheads In Saltwater Aquariums

The water in the oceans is constantly in motion. It should be moving in your saltwater aquarium, too. The critters not only like it, they depend on it.

www.thesprucepets.com

 

[mdb_talon]

Using your math skills.. duh

Fill a bucket to a certain number of gallons and set a stop watch.

Them apex sensors.. they got your money. when a 3 dollar bucket should be more accurate.

Edit, here I find a link for you with steps

The Many Uses For Powerheads In Saltwater Aquariums

The water in the oceans is constantly in motion. It should be moving in your saltwater aquarium, too. The critters not only like it, they depend on it.

www.thesprucepets.com

This becomes pretty difficult when dealing with high GPH pumps unless you have some large containers. Really need to run at least a minute to get a fair reading. Even at half the 2600gph rating that's over 20 gallons.

 

[KStatefan]

It just sucks overall because I need to know the flow to the UV, I don't really care too much about the main return.

How am I supposed to hit suggested targets of the UV if i don't have an accurate depiction of the GPH lol?

They can not tell you what it will perform at in you setup since every setup is different. Most of the pumps have flow charts to help.

 

[Tamberav]

This becomes pretty difficult when dealing with high GPH pumps unless you have some large containers. Really need to run at least a minute to get a fair reading. Even at half the 2600gph rating that's over 20 gallons.

Hm well I don’t know, I got me a 30g and 80g brute. Nice for storing water.

Can go buy one and do it then return it. A little water won’t hurt it

 

[92Miata]

All of the "Rule of thumbs" about elbows and fittings and such are nonsense.

There are a bunch of dynamic head height calculators that work well - and are relatively accurate. Just google and find them.

The biggest factor is velocity of the water - and the biggest determiner of that is pipe size. A straight shot from sump to display using 1" pipe is about 12 feet of dynamic head, which gets you down into the range of an Apex flow meter's accuracy range (and that's ignoring that the flow meter itself is a big restriction)