Pump Recommendation + Other Stuff

J

Jurupari Man

The Masked Tortilla
May 29, 2001
83
4
8
New York, NY
I'm in the process of setting up a 270g tank (84x24x31). I should mention that it will actually be a CA cichlid tank, but I need help with water pumps, plumbing, etc., which you saltwater guys are so familiar with...

Anyhow, first of all I plan on having the tank drilled in the bottom with two overflow boxes, one on each side. I believe the drain holes are to be 1". Am I correct that the drain rate for a 1" hole is approximately 600 gph? If so, then that would be an overall drain rate of 1200 gph. The drains would be plumbed to a wet/dry via 1" PVC.

My next question concerns the pump. What would you guys recommend as the best way to match that flow? I need a very quiet pump. The top of the tank will be about 5 ft. off the floor. Quiet Ones? Little Giants? Please give me some suggestions on that... I suppose the size of the return holes will depend on which pump(s) I use, but will probably be either 3/4" or 1"?

And lastly, would you all recommend using the Durso standpipe on the drains? I want this tank to be as quiet as possible.

Thanks so much!
Itchy
 
Quiet One's are probably the most silent high-flow pump I've ever used, although I have no experience with the new design. The only drawback with them is that they loose flow very rapidly against backpressure. With a 5' head, my guess is they'd only be moving around 700-800 gph. My recommendation, therefore, would be to use 2 quiet ones plumbed in parallel. You'd have a bit more flow than you want this way, but you can reduce that to suit using a ball valve -- this will in no way hurt the pump as long as you put it on the discharge side, not the inlet. Also, for best efficiency and maximum silence, there are a few tips on plumbing -- especially on the pump inlet, try to have a length of straight pipe, at least ten times its own diameter in length, between the pump and any other fittings; the reason for this is it will "smooth out" turbulence in the water stream produced by the fittings that can lead to cavitation within the pump, which produces noise and vibration. Use of 90-degree "sweeps" or 45-degree angles rather than 90-degree angles will help with this.

As far as the stand-pipes go, I would say, experiment. Whether they will be of benifit will depend on the exact flow characteristics of the tank. Basically, a tank gurgles when air and water are drawn in together through the same opening. A durso stand-pipe simply forces the air and water to enter through different holes -- but this is only an issue if air is entering the plumbing. As long as your plumbing is not falling into a siphon-purge-siphon rhythm, you may simply be able to run the water level in the overflows a little higher (ie, slightly more flow, so that the pipe is running at MAXIMUM capacity all the time) so that no air enters the pipe at all. This situation is ideal, as it is basically completely silent.

Hope this is of some use to you.
 
Thanks - yes the Quiet Ones seem to be the best bet. Which Quiet One model would you be referring to? Are the ones with the new design different in terms of flow rate? The nwe model 6000 is rated at 1500 gph, the 5000 at 1270 and the 4000 at 1017 I believe (all at zero head).
 
I'm thinking of the original quiet one pumps, of which there was only one model. They were an external-use only pump that looked like a squashed version of a little giant type pump. The old ones did around 1200 gph at zero head. The new ones, of which there are several models, remind me more of a mag-drive. I have no experience with these newer models, and I don't know how the flow rates and head performances match up. However, you should be able to find flow curves either on the box or on the web. Try www.pentairaquatics.com , this is the company that makes the quiet one.
 
Thanks again. I'll make some calls tomorrow to see which Quiet Ones would generate the proper amount of gph... Just another quick question though. I'm thinking of making my drain holes 1.5" instead of 1". This would give a greater flow, but I'm wondering HOW MUCH greater? If 1" holes drain 600 gph, do 1.5" holes drain 900 gph? Or is it more complicated than that?
 
It's more complicated than that. The key here is the cross-sectional area of the pipe, which is determined by pi*radius^2 which is the same as 0.78539d^2. So, with a diameter of 1", we have a crossection of .785sq inches. With a diameter of 1.5", the area is 1.767 sq inches, which is actually 2.25 times the area of the 1" fitting, and therefore 2.25 times the flow rate, ignoring friction, etc.
 
Thanks. I had a feeling there was more to it than that... OK, so say the flowrate from 1.5" holes is about 1400 gph. Would two of those (2800 gph) be overkill on a 270g tank? I need to tell the guy making the tank & the guy making the wet/dry what size holes to drill. And the pump I choose will depend on this as well obviously.
 
2800 gph would be a lot, about ten turns an hour, but there's nothing to say that you have to run the bulkheads at full capacity, in which case you would want to use a durso stand pipe to quiet it down. If there's minimal difference in cost etc, then you might want to go with the bigger ones just so you have the extra capacity if you ever want it in the future. Its a lot easier than putting more in later.:)
 
be careful with those quiet one pumps. Ive seen a few that burned out pretty bad.
 
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