Water movement for idiots?

Ok, I managed to get my RODI up and running and now I'm feeling like I can get my tanks set up with a sump/fuge. I'm good with building it but I can't imagine how I'm going to get the water out of my tank, through the maze of filtering devices and back into the tank without flooding my studio. I know the names of the parts but when it comes to putting them together I get lost. Why is it called an overflow because that sounds bad to me, I don't want my tank to overflow, right? Also, it seems like if you're moving water from one spot to another, how does it know to do it at the same time? Even if you get the same equipment the flow rates are going to vary slightly so eventually there will be problems. I've never used a pump before, can you set the flow rate? When I read through build threads everyone talks about what equipment they use but it is assumed you know the basics. I get the concepts but not those basics.

Thanks to anyone that can help!

Catherine

 

Haha, ya "overflow" doesn't sound so good, but think of it as a controlled overflow from the DT to your sump/fuge. When it comes to pumps, as long as your overflow can handle the gph that the pump produces then you'll be fine.

It's def. nerve wrecking the first time. But if you trust your ability to set it up correctly then don't worry about it.

 

I know how you feel. I am also building my first sump and overflow. I hope that "overflow" does not happen and my wife's carpet and livingroom stay as dry as they are today... She has a fit during top offs and water changes if I splash just a few drops. If during my build I suddenly stop posting it will most likely be that she killed me due to spillage. hehehehe.... RIP :death:

:mrgreen::mrgreen::mrgreen::mrgreen:
Joe

 

Is your tank drilled? If not, you will be using an overflow box. Instead of thinking of the name meaning your tank is overflowing, think of it as a place were the water can FLOW OVER the tank to get to the sump.

As for coordinating the flow rates, you don't have to. You can't adjust the flow rate of the pump, but whether you use an overflow box or your tank is drilled, the water can only flow over the side (or down to the sump) when it reaches the level of the teeth in the overflow. If the water level is below that level, no water will go over the overflow. The pump controls how fast that water level changes in the main tank. If you use a weaker pump, it will take longer for the water level in your display tank to rise.

So, the water can only go over the overflow as fast as your return pump is pumping it. There's no need to coordinate the flow. As long as your overflow is rated to handle more than the pump can handle, there's no risk of the tank overflowing.

In short, the water can only return to the sump as fast as the pump can push it back into the tank.

 

You said that very well. But I still worry about water on the floor...:Cheers:

 

What you need to do to help avoid water on the floor is fill the tank up to where it starts to over flow to the sump. Then fill the sump up to an inch below the rim. Turn the pumps on. Let it run for a bit and make a mark on the sump return section where the water line is. This will be you "full" mark. If you loose power, the water in the plumbing will drain back to the sump. But since you marked where the full line is while everything is running, when it stops, it will only drain to an inch of the top of the sump.

Also, drill a smalle 1/8 or so hole right at the water line of the DT on the return plumbing. This will prevent any back syphoning of the tank water.

It really is as simple as water flows down hill. If you pump it up, only as much as you pump up will flow back down.

 

should have mine running this weekend. my overflow is in the mail and should be here in a day or 2. I have a thread running on my changes and will be posting pics and results there. Thanks for all the help.

 

+1 Bifferwine and BJ
Good luck guys on setting up your sumps! :x:

 

hahahahahaha

actually, i'd like to add one thing to everything above.... the overflow has a rated flow rate. Lets just say your using a 300gph unit, then your return pump, (and figuring for head losses) should end up pretty close to that #.

the reason for this is that if you use a small pump, lets say 100gph, then bubbles will collect in the u-bend tube and will eventually build up and break the syphon and cause problems... either the return pump will go dry, or the dt will overflow, or some combination...(go ahead, ask me how i know...)

If you use a BIG pump, lets say a 500gph, then you have too much flow and you can again run the return pump dry, or could overflow the DT.

now in each of the above examples, i didnt figure in the head loss, so, lets say, just for giggles that we have a 40% loss due to the lifting height(head loss)
so, that means that the first pump only actually gives us 60gph(way too small for the overflow) or the second one is 300gph. now thats just about right, that is enough flow to push all the bubbles out of the u-bend tube, and to keep it all in ballance.

now, just as an extension of the example, lets say that the second pump example was 750gph and not 500. well then we would have 450gph to the display tank, and thats more than the overflow can handle. What you do in this situation is that you would put a valve inline between the return pump and the DT and you can "trim" the flow down from the 450 to the 300 that you need.

Now there are some other creative things that you can do with this extra flow, rather than just pinching it off with a valve, but i'll leave that for another time....


just thought i'd add to the confusion..

 

I have never used a U-tube style overflow, but I did use a CPR overflow box for years and never had any problems with floods or it losing siphon.

 

Oy.

C

 

all of that makes you wish their was a hob filter that would be good enough for a reef tank dont it. Psst but their is if you dont mind cleaning the thing every week. Dont let Biff know I said that. I know the party line, sumps are great more volume mean more stability. Cansiters and hob filters are bad. Sumps scare the shit out of me. Would be one time saltwater all over the house be no more tanks for me. But hey to each thier own. Eventually I will have a sump, when I upgrade to my next tank. However it will be predrilled or drilled on my own. I am not lucky enough to trust my luck on a tube overflow.

 

yea it made me pretty nervous at first too, but then after i gained an understanding of the physics of how it works, and what its short commings are, now, i'm fine with it, if it does something i dont want it to do, i know how to adjust to make it work...

I agree, i'll never have another one thats not drilled, but since this one is already up and running, i'm not gonna try and drill it now...

 

I guess I don't understand exactly the path that the water takes, I've never seen one of those overflow things in action. I'll search youtube and see what I can find.

Wow, this guy yacks a lot but it totally helped!

[ame]http://www.youtube.com/watch?v=TdpaQ_A-tqk&feature=related[/ame]

thanks,
C

 

i would basically agree with everything he said in that video except mounting the return pump that high..

if you mount the pump that high, then you have no reserve volume for evaporation. not to mention that if you were to follow his advice on mounting the pump that high, and you have an ATO on your tank, then mounting the pump that high becomes pointless, cause if the syphon breaks, then the pump pushes all the water out of the return section, the ato will be trying to fill that section back up, and you still end up with the main tank overflowing...

 

+1 pk5
Seems he hasn't had a lot of experience doing sumps. He will learn when disasters happen.

 

exactly, he will learn when he burns up a pump, it shorts internally, and puts electricity into the water and kills everything in his tank...

 

I just dont understand why he wont waste his money on a pump that is properly sized for his overflow but will go and buya pump that will shut off if it gets out of the water.

It is very informative but he did not size his overflow to the pump size. And with the clear tubing, he will also start to grow algea in side the tubes once he gets his light in there. I actually prefer to hard pipe everything in PVC. But I just dont like the look of tubing going every which way.

 

well, the principal that he is using is sound, the smaller tube will infact allow him to run a lower flow rate and not have the bubbles collect, but your right about the algae... My hard u-bend tube is clear and its never grown anything, but then the light isnt directly on it either... that may change when i do my canopy, in which case, i'll be taking a foot long chunk of 1inch pvc pipe, putting some red heater hose inside it, and then heating the pvc in hot water till its soft enough to bend, then i'll make my own opaque tube(the heater hose keeps it from colapsing or kinking) and yes i know this works, cause i made a buttload of candy canes for my grandparents front yard using this exact method.

 

I was gonna say you can also fill it up with sand and heat it with a torch. Just dont get the flame too close or else it will burn. But the sand keeps it from kinking.