Sequence pumps and backpressure

[Anonymous]

Hey everyone,

I am going to be re-plumbing my tank in the future and want to go with a big closed loop in the in the crawlspace below the tank (where my sump is). I am trying to decide which Sequence to go with - I am thinking I should go with the 5800, but am worried it will be too much flow and wondering how these pumps take to being dialed back. Any thoughts would be helpful!

I am planning on running the return to a manifold with 10 3/4 valves,. 8, or less, of them to be used to push the water in the tank counter clockwise, 1 for the above tank 'fuge, and one extra.

 

[Anonymous]

As long as you throtle it on the discharge you can cut it to 50% or less depending on the pump. If you need to choke it that much you need a smaller pump. Putting a valve is no different that having more lift. Why not add a few more outlets and lower the velosity but keep the flow rate?

 

[npaden]

I have a old sequence 6000 that I kept throttled back for a couple years because it was to much flow for my sump to handle without creating bubbles. No issues that I am aware of - it is still running strong. Now I use eductors to throttle it back instead of a ball valve.

FWIW, Nathan

 

[Anonymous]

Great - the two people I as hoping would respond!

Wazzel, on the 5800, how many 3/4 outlets (I would go 1 inch, but want to use loc line) in total do you think I need to use the maximum flow rate for the pump?

 

[npaden]

If you were to get 4,500gph out of the pump after friction losses (which seems resonable for that pump curve) that would give you 562.5gph out of 8 - 3/4" outlets. That would be a velocity of just over 6.8 ft/sec out of each outlet. A little bit fast but if you didn't put anything directly in it that would work good. If you bumped it to 10 - 3/4" outlets you would drop it down to 5.4 ft/sec and 12 outlets would get you to 4.5 ft/sec which is closer to what I would call ideal.

Of course this depends on your final plumbing specs to figure out what your friction losses will end up being. If you oversized your plumbing you could get more than 4,500gph out of the pump and if you split it to a bunch of 3/4" pipes right at the start you probably wouldn't get that much flow out of it.

[edit] I changed the flow around a bit after I looked at the pump curve. I don't have the curve for the 5800 but based on the curve for the 6000 it will handle 13' of friction losses and still kick out 4,500gph so you might get a little more than 4,500gph.

Another way to maximize your flow without increasing your velocity may be to put a few larger diameter outputs in selected places where you don't need locline. Of course on a setup like this it will be VERY important to have a ball valve on each output so you can control the flow to them otherwise you are going to end up with one output with 1,000gph and some with 250gph. [/edit]

HTH, Nathan

 

[Anonymous]

Helps a lot Nathan. I could go with 10 outlets and just dial them down if ft/sec is too much. Also, I can make 2 of the outlets 1 inch (as vertical spray bars) which should allow me to pump any extra flow through them. I could even convert the 3/4 locline to 1 inch for the last couple inches which should slow the flow.

But the major question I think has been answered - I can dial the pump back. So, I think I will go with the 5800. Well, that could easily change in a day!

 

[Anonymous]

BTW, this is for a 5x2x2 150 gallon tank. You guys think the 5800 is too much flow?

 

[npaden]

Not such a thing as too much flow.

Too much velocity yes but never to much flow!

I think you will be fine.

 

[Anonymous]

Sweet! Bye bye evil sand bed!

Thanks!

 

[Anonymous]

After seeing npaden I do not have anything to add. My responce would have been extreemly similar. As far as the flow I will have +/- 3300 gph comming out of a minifold that has four 1" outlets, three 1/2" outlets and eight 3/16" holes in my 60. On top of that I will have another +/- 700 gph from the return. I agree with the max the flow min the velosity approach.

 

[npaden]

Sweet! Bye bye evil sand bed!

Thanks!

If you pay attention to your velocity your sand bed will be fine.

I'm running 15,000+ gph in my 415 with a 750lbs of southdown sand in there for the last 3 1/2 years. Of course I have some sand dunes now:

Thinking about changing things around a bit and increasing the flow to 25,000+ gph just for the heck of it.

 

[Anonymous]

I meant evil sand because I am in the middle of my second disturbed sandbend RTN event. Sad me.

 

[Anonymous]

Back on the Sequence route again, thats good. PM me Rich.