BRS investigates suggestion

[Sleepydoc]

Was reading another thread and came up with another video idea for you guys - compare specified vs actual flow ratings on the more popular pumps as well as flow per watt consumed. Now that Apex has their flow meters, this should be relatively easy to accomplish.

 

[TaylorPilot]

I would be interested to see how those flow meters are calibrated, and if they are done using a known traceability standard. I have a feeling those gauges are more for determining when something changes, not getting an actual number. I can't find literature anywhere on their site stating their accuracy. Plus they state they are only good to 1500 GPH. I would be interested to seeing it as well. I think peopel would be surprised at what those DC pumps actually put out with standard heads.

 

[Vuuduu]

I would like to see this as well. I purchased a Vectra L1, which is rated at 3100gph. I am using 1" plumbing, which is with the blue fitting that came with the pump. If it came with a 1.25, I would have used that, but the 1" is what it came with in the box, so I assumed the rating was with that plumbing? A 1.25 white adapter is available separately.

I set up my system and I was showing around 400 gph?!? I was expecting around 50% drop from listed rating with plumbing and head pressure, not 87%. Wasn't sure what was wrong, if it was the pump or bad sensor... so I bought another pump, I went with the varios-8, since I wanted to check this pump out anyways. It's slightly lower rating at 2700 gph, but still close enough to compare numbers I thought, and yeah, like 350gph. So I bought a new sensor, didn't really want/need another one but whatever. Plugged it in and bam! guess what? same readings. So I ruled the faulty sensor out.

SO whats the problem here? I assumed maybe my plumbing is reducing the flow waaaay more than I expected. So I fabricated a pipe with a 18" raise, then an elbow then a few feet of straight and then the sensor to try and get a close to no head loss reading.....guess what it was? 1300gph on L1 and 1100gph on the varios-8. SO an almost straight shot to the sensor and these pumps are both working around 40% of the listed gph.

My tank is a reefer 525xl. I was shooting for 800-1000gph because that's what Redsea recommended, as well as the standard for the Triton Method wanting around 10x volume. But that's not going to happen, I'm just going to live with the 400 gph and hope it works for me...its cycling right now.

I was even considering buying the Abyzz A400 (4800 gph normal mode) to get my 10x, but if they rated similar to the others it would still be only around 600 gph on my system.

If BRS did do a comparison, it would help with what performance we could really expect to get from out pump purchase.

On a side note, I would be very interested to know what gph the BRS 160 had with the L1, and what gph they are getting now with the Abyzz.

 

[NY_Caveman]

@Bulk Reef Supply, @Ryanbrs
I agree. Great idea for a video. Pumps, gyres, powerhead, etc. what is stated max power flow compared to actual max power flow. Perhaps even more interesting, but more involved, actual flow at different percentages of power.

 

[rockskimmerflow]

I would like to see this as well. I purchased a Vectra L1, which is rated at 3100gph. I am using 1" plumbing, which is with the blue fitting that came with the pump. If it came with a 1.25, I would have used that, but the 1" is what it came with in the box, so I assumed the rating was with that plumbing? A 1.25 white adapter is available separately.

I set up my system and I was showing around 400 gph?!? I was expecting around 50% drop from listed rating with plumbing and head pressure, not 87%. Wasn't sure what was wrong, if it was the pump or bad sensor... so I bought another pump, I went with the varios-8, since I wanted to check this pump out anyways. It's slightly lower rating at 2700 gph, but still close enough to compare numbers I thought, and yeah, like 350gph. So I bought a new sensor, didn't really want/need another one but whatever. Plugged it in and bam! guess what? same readings. So I ruled the faulty sensor out.

SO whats the problem here? I assumed maybe my plumbing is reducing the flow waaaay more than I expected. So I fabricated a pipe with a 18" raise, then an elbow then a few feet of straight and then the sensor to try and get a close to no head loss reading.....guess what it was? 1300gph on L1 and 1100gph on the varios-8. SO an almost straight shot to the sensor and these pumps are both working around 40% of the listed gph.

My tank is a reefer 525xl. I was shooting for 800-1000gph because that's what Redsea recommended, as well as the standard for the Triton Method wanting around 10x volume. But that's not going to happen, I'm just going to live with the 400 gph and hope it works for me...its cycling right now.

I was even considering buying the Abyzz A400 (4800 gph normal mode) to get my 10x, but if they rated similar to the others it would still be only around 600 gph on my system.

If BRS did do a comparison, it would help with what performance we could really expect to get from out pump purchase.

On a side note, I would be very interested to know what gph the BRS 160 had with the L1, and what gph they are getting now with the Abyzz.

Those numbers dont surprise me in the slightest. Beyond the Abyzz and red dragon DC pump lines you wont find much in the way of head pressure handling in the typical chinese sourced DC designs. Not knocking those that use them, but lets think about things critically - there is a finite efficiency that can be squeezed from a given wattage input in the form of either flow or pressure. You cant look at a pump drawing 90w max for example and expect it to be as stout in the face of plumbing restrictions as one that pulls 180w. Even if the 90w max pump's box says it moves 2x the gph of the 180w pump. If you want closer to 800gph in your case, try a fluval SP6. The askoll made motor blocks and impellers are as efficient as nearly any DC pump in terms of gph/watt and way more reliable than anything else in the sub 300 dollar range.

 

[Vuuduu]

Yeah, I understand the head pressure loss from height, which size pipe used, and all the bends add up. The main thing that disappointed me was my test straight out the pumps with virtually no head pressure loss (or very minimal at least) being around half of the box rating.

I’m actually content with what it’s doing right now..... I’m keeping it at 400gph which seems like enough turnover through the sump at this point, only reason I was trying for the 800-1000 gph was what triton and BRS said to strive for,

 

[Sleepydoc]

Yeah, I understand the head pressure loss from height, which size pipe used, and all the bends add up. The main thing that disappointed me was my test straight out the pumps with virtually no head pressure loss (or very minimal at least) being around half of the box rating.

I’m actually content with what it’s doing right now..... I’m keeping it at 400gph which seems like enough turnover through the sump at this point, only reason I was trying for the 800-1000 gph was what triton and BRS said to strive for,

DId you try changing the plumbing to 1.25” or 1.5”? I’m guessing the 1” plumbing is causing more head loss than your’re expecting.

 

[MSOEME2009]

An L1 rated for 3100 GPH or 51.6 GPM would have a velocity of 23 ft/s (180 ft /100') which is astronomical in a 1" SCH. 80 pipe. That pump should be using 2" to reduce it to 5.6 ft/s (5.29 ft/100').

Just that little "test" piece already put 12'+ of head on the system with a 1" pipe.

I tried to help a fellow reefer out in this thread by breaking it down.

https://www.reef2reef.com/threads/return-plumbing-size.371225/#post-4562681

It's all a matter of fluid dynamics. Unfortunately, most pumps come (in every industry) come with an outlet size smaller than what should be used. I use pumps with 6" outlets which I have to go up to 10" pipe with immediately. A pump rated for 1300 GPH in a 1" SCH 80 PVC pipe has a velocity of 9.63 ft/s, that's still high. Shoot for 5-6 ft/s as a rule of thumb.

 

[Vuuduu]

Thanks for your insight, and that was some interesting reading on pump flow.
So I have another question. I'm using 1" right nowfrom my pump, which is on a redsea reefer though, and the return goes through a pipe that seems to be aprox 3/4", which at the top there's a very small 90 elbow which clicks into the overflow and flows water into the tank. That elbow is about 1/2" ID. Since it goes down that small, is it like I am using 1/2" on the whole system? Should i fabricate my own pipe instead of the supplied one? would it make that big of a difference if at was all 1"? also I have a few unions, and 2 ball valves which even though they are 1", the ID is about 3/4 on them. So are all unions/valves bad for the pumps in that regard?

 

[MSOEME2009]

The pressure drop from running 1/2" is only the physical 90 from what you described. To do a total system pressure drop you'd calculate total 1" pipe drop + 3/4" drop + 1/2" drop. Depending on what pump you're actually using, that 90 could be the difference between a few hundred GPH. Take an imaginary tank of water, and put a hole in it. The bigger the hole, the more flow. However, you can use positive pressure to overcome the difference in hole size (to a point). This is in essence your pressure drop after a pump. You're using positive pressure to overcome loss.

 

[rockskimmerflow]

The pressure drop from running 1/2" is only the physical 90 from what you described. To do a total system pressure drop you'd calculate total 1" pipe drop + 3/4" drop + 1/2" drop. Depending on what pump you're actually using, that 90 could be the difference between a few hundred GPH. Take an imaginary tank of water, and put a hole in it. The bigger the hole, the more flow. However, you can use positive pressure to overcome the difference in hole size (to a point). This is in essence your pressure drop after a pump. You're using positive pressure to overcome loss.

Yup, I agree with that assessment for sure. In a lot of these prefabricated tank/plumbing setups I see situations where using a larger diameter return line up the the tank then splitting into 2 or more half inch outlets would vastly improve the flow vs. the narrowing of the single return line down to small diameter before it hits the aquarium. I like the velocity offered by a half inch return nozzle, but much prefer to run 1 inch or 1.5 inch line up to a T which the houses reducer bushings to step down into half inch locline. 2 x .5" nozzles can actually flow a decent amount if they are supplied with appropriate upstream piping and a pump with decent pressure. They are useless however if the line feeding them has already chewed up all the muscle the pump had to offer.