Closed loop not as great as I thought, need some help

[Rare Angels]

Hello everyone,

I recently contructed a closed loop manifolf on my 40 breeder tank.

The pump is a mag18 and the plumbing is all 1.0". There are 4 outlets, 2 in back and 2 in the front. The tees for the outlets have 1/2" outlets.

There doesn't seem to be much flow out of any of the outlets and tonight I came home and barely and water was coming out of any of them...like I am talking it was just leaking out. I turned the pump off and then on again and it went back to how it had been.

The pump is directly behind the tank and rests at the same level as the bottom of the tank. Its mounted with the outlet pointing straight up and the inlet level with the stand.

Do you think there is air trapped in the plumbing or.........?

Any help would be much appreciated.

Dave

 

[zoozimmy]

maybe

 

[Rare Angels]

Bump

 

[reverendmaynard]

How is the intake plumbed. Bulkhead or over the top? 1" pvc for intake?

1" for the intake is really too small for that pump, IMO. I believe the recommendation is to step up an additional 1/2" over the pump's intake size.

 

[GMAX]

Got a bunch of 90 degree angles in your plumbing? 90s are a killer for flow as water does not much like to go around corners. If you have the ability to use flex pipe or if 45 degree elbows can be used you will see much better flow.

 

[Icefire]

you need 1.5" inlet for a mag18

 

[wuelfman]

on a closed loop there is no head pressure 90 degree pipes dont matter.
both intake and outtake need to be below the water line
do you have a picture that would help alot

 

[gh0st]

Last I checked you lose about 5-10% for each 90 degree.

Even though it is a closed loop, you will still have a small amount of back pressure. Not as much as pumping against gravity, but there will still be some flow lose from the water being deflected through the elbows.

 

[Liquid Hobby]

I initially had some MagX(12 maybe) pump for my closed loop on my 40 breeder with 3/4" pipe all around. During fresh water tests, I found what you did, flow was woefully inadequate. So, I redid the entire thing based off a pressure rated pump (panworld ~ 1150GPH), which made a HUGE difference!

Also, your plumbing is small. I run a 1 1/2" intake and 1 1/4" returns to 4 outlets in the tank, split in tank with locline nozzles. Plenty of flow now!

Click on my red house to see my 40 build thread. I went through several CL iterations before stepping up and getting the appropriate pump for the job. I was also cautioned away from running a Mag outside the water as the impeller housing tends to leak over time, or so I was told...

T

 

[PrangeWay]

In 1" piping, at Mag 18 flows, each 90 will result in about 1" of head. So you'd need 12 of them to even generate 1' of head.

This is considered a minor head loss and is computed by K (V^2 / 2g), where K is a loss coefficent based on what you're using (bend, vavles, inlets, outlets, etc). The K for a 90 is around .9, while the K for a ball valve would be 10, hence try to use gate valves in plumbing with the lower K of 0.15 .

Also rare did you extend the intake up a bit and have a threaded cap? That way you can fill it full of water, letting the air come out the top...


PW