# what do i need to know about flowrate out of sump??



## johnnytrax (Nov 30, 2010)

hi everybody!
im kinda new to all this still.. and im turning my focous to building my own sump.... any hints? tips? suggestions? tidbits of knowladge?... learn me please!!

most of all... what do i need to know about the flow rate??
into\out of the sump?? if i use gravity to drain? what size pump do i need?

thank you all for reading!


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## hdrob (Dec 6, 2010)

There are tons of sites you can google for sump system designs. I did that and my DIY sump is working great. I would go with the largest reasonable drain and the pump you go with would determine the amount of flow. I built my own HOB overflow and had no problems with it. I think you can buy a decent sized HOB overflow for about $125. I have a 90g and my pump is rated for 385gph. Even if you go with a higher output pump you can always plumb a bypass back to sump on the feed line and throttle it down that way. Don't forget about head pressure. A pumps rating goes down the higher you have to lift the water to get back to the tank. I think the general rule for FW flow is about 3-4 times turnover.

and... read, read, read.


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## Rastapus (Apr 21, 2010)

Well summarized. Acrylic is the preferred building material as you can modify things easily down the road, glass is more restricting. Designing your own is fine if you have a specific design in mind. Years ago I had a few glas sumps, worked fine but over time I became frustrated with various challenges such as how to add a float switch etc. IF the sump had been acrylic this would have been very easy. Also external pumps are preferred to avoid heat transfer so it is better to go with a drilled sump, again in acrylic much easier and more reliable.
Good luck!


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## johnnytrax (Nov 30, 2010)

thanks for reading and your responce, it does help... but like i said im new... 

but i really just want to know about the flow of water from the display tank to the sump??... im not smart, just new! is there some kind of formula? a ratio? so i dont overflow my sump? or even my display tank?

again, thanks for all the help... im a sponge!, teach me!!


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## spit.fire (Jan 3, 2011)

johnnytrax said:


> thanks for reading and your responce, it does help... but like i said im new...
> 
> but i really just want to know about the flow of water from the display tank to the sump??... im not smart, just new! is there some kind of formula? a ratio? so i dont overflow my sump? or even my display tank?
> 
> again, thanks for all the help... im a sponge!, teach me!!


if properly set up, your sump and display tank should never overflow, what style overflow does you main tank have?, how i set mine up, i basically filled my tank and the sump with all my pumps turned off and that way it lets me know what my water level can be without ever risking an overflow. Basically the volume pumped into the main tank is drained out at an even rate so it can never over flow, just make sure your pump is not pumping out more water than your drain out of the main tank can handle. (my drain is substantially larger than my feed.


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## spit.fire (Jan 3, 2011)

also once you have both tanks filled, turn you pumps on, let them run for awhile and put a clear mark on you sump for where the water level is so you can do topups without every worrying about floods


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