How much can you safely restrict a water pump's flow?

[bjoiner]

I have a "Rainbow Lifeguard Quiet One 6000" external pump that I would like to use on a new chiller for my tank. The pump is rated at a little over 1500 gallons per hour. I'm debating between a couple of chillers, one that has a max flow rate of 1300 gph and another that has a max of 960.

I know that you are only supposed to put any valves on the outflow side of the pump and lessening the flow to 1300 from 1500 doesn't seem like it would be that big of a problem, but I was curious it cutting it back to 960 would be hard on the pump in the long run.

(I'm leaning towards the bigger chiller as although it may be overkill for my tank, it would let me have a little more water circulation.)

Also, I would like to hook this up to a SCWD wavemaker to give some more random-ness to the flow.

 

[IslandCrow]

I wouldn't think reducing it from 1500 to 1300 would be an issue, but it would be pure speculation on my part for 960 gph. What if you split the flow and had half of it going directly back to the tank, while the other half goes through the chiller first and then to the tank? It may be a little tough to guage exactly how much flow you're getting through the chiller, but if you shoot for right between the min and max flow, I would think you'd be fine.

 

[rayjay]

You don't have to throttle the flow back if you run a parallel circuit with one circuit going through the chiller and the other going back to the tank.
You would only have to restrict one line and the extra flow will go through the unrestricted circuit.

 

[Anonymous]

Does the chiller have a maximium flow rate? If not, just let the pump go full throttle.

 

[bjoiner]

I wouldn't think reducing it from 1500 to 1300 would be an issue, but it would be pure speculation on my part for 960 gph. What if you split the flow and had half of it going directly back to the tank, while the other half goes through the chiller first and then to the tank? It may be a little tough to guage exactly how much flow you're getting through the chiller, but if you shoot for right between the min and max flow, I would think you'd be fine.

It doesn't look like it's going to be a problem if I go with the bigger chiller. I was reading on the pump box that at 2' the pump's flow drops to about 1300. Add another bend in the pipe and it should be well under the chiller's max.

I'm still debating if the chiller is worth it. They aren't cheap and so far my house temperature doesn't get that hot. (I think I need to spend a day and monitor the temperature - It would be nice if I could get a read out over a 24 hour period.)

 

[IslandCrow]

You're right, chillers are definitely expensive, and I wouldn't rush into getting one, but here are the big benefits as I see them:

- More stable tank temperatures reduce stress on fish and to a greater extent corals. Couple the chiller with a temperature controller, and you can keep extremely stable temperatures (mine generally don't fluctuate more than .5 degrees from day to day).

1) If you don't have someone in the house all the time, you can save some electricity just cooling your tank instead of the whole house.

2) If you lose power for an extended period, it takes a much smaller generator to power a chiller than it does to power your A/C.

3) Just one more backup. . .if a heater gets stuck on, a pump overheats, etc., the chiller should at least help keep the tank temps from spiking.

With all that said, many people get by just fine with some strategically placed fans even when the outside air temperature is well into the 80s or even 90s. I use a chiller mainly for reason #1 because I spend much more time out of the house than in, and it's actually reduced my electric bill by $20-$30 a month during the summer.

 

[Anonymous]

What pressure is that flow?

 

[bjoiner]

I believe the intake and output were both 1" diameter

 

[ihopss]

price ? what's in the tank$$ how much$$... make them( intake, exhaust) 1"1/4 that will cut your flow down.

 

[ihopss]

price ? what's in the tank$$ how much$$... make them( intake, exhaust) 1"1/2 that will cut your flow down.

 

[Anonymous]

You are not going to be getting 1500 gph out of that pump. Once you figure in the static lift and line loses I would say you are going to be getting right around 900 gph to you tank.

See the performance curve I attached for you pump. Flow is on the bottom and losses is on the vetical. Most people have around 4 ft of lift and 2 ft or so of losses. Look at the 6 ft line on the left and follow it over until you intersect the pump curve. Follow that point down to the flow line and that will tell you what you appoximate flow will be.

 

[Anonymous]

oops. My source for the curve.

http://www.marinedepot.com/aquarium_pum ... mation.asp

 

[bjoiner]

Thanks Wazzel. Now I just need to come up with the money for the chiller.

 

[Anonymous]

If you are going to add a chiller look at a lot more losses and a lot less flow.

 

[IslandCrow]

Agreed. I had a lot less flow than expected after it went through my chiller. I don't suppose anyone knows of a head loss calculator that can actually factor in chillers?

 

[Anonymous]

There is no publised data that I know if for chiller head loss. The manufacturer should be able to provide that.