bigger return pump does not increase flow

[youngfish]

I have a 180G with 1" return and 1.5" drain.
I am using 1/3 HP JBJ chiller with 3/4" hose connector. So used 3/4" pipe throughout the return line.
I was using eheim 1262 as return pump. Hose it to 3/4" pipe, go through chiller and then back to aquarium. I feel that the return flow is not good enough so I got a Mag 1800 which doubles GPH.
But after I hook it up, surprisingly, it does not increase flow at all. The water level in the main tank stays at almost the same line....

The aquarium return nozzle is approx 4 feet from the sump water. According to flow chart, I should be getting around 800GPH out of eheim 1262 and 1200GPH out of the Mag 18. But the actual flow is definitely way smaller than that.

Anyone knows what is going on?

 

[NYreefNoob]

your only going to get x amount of water through a x size hose, and return really isnt used for flow, thats what power heads are for

 

[youngfish]

can I get at least 800GPH for 3/4" hose? I think I should be able to. But the actual flow I get is much less than that.

 

[youngfish]

Is it possible that chiller blocks much of the flow?

 

[JimmyR1rider]

You're chiller is nothing but an open pipe. If you have your pump also supplying that with no ball valves to rate that flow rate you're putting a decent amount of your flow through that right back to your sump and gravity(head loss) is working against you and the water will go the path of least resistance. In other words whatever's the lowest/ shortest route of travel

 

[jaa1456]

Also I believe the 3/4" pipes are only rated for a max of 600GPH.

 

[NYreefNoob]

plus every bend and turn decreases pressure, personally i have always ran a low flow through my sumps as it give more contact time for the skimmer, less chance of bubbles also, oh yeah and less electric from smaller pump, mag's use alot of power and generate alot of heat and are known for the screws rusting out

 

[edd]

why don't you run the chiller off the ehiem on its own. run your return from sump on the mag. sounds like you have it hooked in series, from pump to chiller to tank. could be a lot of turns and resistance.

 

[youngfish]

3/4" is return line, not drain. So it is not a problem to achieve high GPH.
I could hook the chiller to its own pump. But then I would have an extra pump to set up.
It is much better to have chiller inline with return pump. It saves lots of piping and energy.
I dont really need much flow. I was asking 800GPH for 180G. This is not a big flow to the sump. But I think I was getting just 200-300GPH for the sump. That's too low.
After I upgraded eheim 1262 to Mag 18, the flow stays almost the same. This is what confused me.

 

[edd]

i have 2 1262s on my 150.i measured one from locline in tank it was less than 400gph. eheims curve chart rates it at 600gph at 5ft head. from my pump to top of tank is 5ft. so with a couple of 90s i guess 400 is about all your going to get.

 

[greenstreet.1]

try bigger hose or pvc got the 1262 my tank may not be as big as yours but my flow is crazy.pipe size increases flow i be leave.

 

[JimmyR1rider]

3/4" is return line, not drain. So it is not a problem to achieve high GPH.
I could hook the chiller to its own pump. But then I would have an extra pump to set up.
It is much better to have chiller inline with return pump. It saves lots of piping and energy.
I dont really need much flow. I was asking 800GPH for 180G. This is not a big flow to the sump. But I think I was getting just 200-300GPH for the sump. That's too low.
After I upgraded eheim 1262 to Mag 18, the flow stays almost the same. This is what confused me.

Doesn't matter drain or return. The max gph is the max that can be pushed through that pipe. More can be done but the pressure you would have to supply to increase the flow is more than any pump you'll fit in your system and would probably burst the PVC or blow a fitting.

http://flexpvc.com/WaterFlowBasedOnPipeSize.shtml

 

[ELMSS12]

If your going thru 3/4" hose with barb fittings you are necking it down to approx a 1/2" hole. I went thru this when I setup my 75. I have a 1" hose off pump to 3/4" pvc straight up to tank. Even with a couple 90's and a manifold setup I can get alot of flow to rank if I want.