# Water Changes with a Sump



## timbo6684 (Aug 29, 2010)

I'm looking for tips/tricks/advice...or whatever to help with doing water changes in a setup that has a sump. Basically a step by step so I don't overfill the system. Thanks in advance.


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## lilscoots (Mar 13, 2012)

Mark a "filter off" line and a "filter on" line on the side of the sump. To set these, Make sure there's a siphon break in your return line just below the desired tank water level. Turn everything off, let the tank drain into the sump until it stops draining. Add water to the sump so it's full but still an inch or two from overflowing. Mark the off line if you want at this level. Turn everything back on. After a few minutes mark a line at the level of the water in the chamber where the pump is or draws water from, this is the "filter on" line. You can use this line to top off the tank b/n water changes and know that if the power were to go out, the system won't overflow.


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## nodima (Oct 3, 2002)

I know the min and max water levels in my sump. So I drain 50% of the water from the tank and as I am refilling, I turn the pump on as soon as water starts flowing down the overflow. This usually reduces the water in the sump to around the min level as the pipes fill. I continue to add water with the sump running until the water level in the sump is where I want it. Shut off water and it's done. It is a good idea to keep hose connected and let the system find it's equilibrium again, and that way if you need to add more water it is simple.


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## martino (May 12, 2013)

nodima said:


> I know the min and max water levels in my sump. So I drain 50% of the water from the tank and as I am refilling, I turn the pump on as soon as water starts flowing down the overflow. This usually reduces the water in the sump to around the min level as the pipes fill. I continue to add water with the sump running until the water level in the sump is where I want it. Shut off water and it's done. It is a good idea to keep hose connected and let the system find it's equilibrium again, and that way if you need to add more water it is simple.


+1


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## zimmy (Aug 13, 2010)

I'm about to set up a sump on new tank. My old display tank (DT) will actually be the sump on the new tank. The new tank will have a valve connected about half down the side with a hose attached leading to a drain in the floor to allow water changes if I want to drain the water directly from the DT.

Is there any advantage to doing the water changes just from the sump?

The drain tank will be an 8' 240G the sump will be a 5' 120G if that makes any difference. The sump will also be in an adjacent room so it will be easily accessible.


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## caldwelldaniel26 (Jun 11, 2017)

Where is the hole for this bulkhead going to be located on the display tank and is it connected to one of the drains that goes to the sump?


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## zimmy (Aug 13, 2010)

The bulkhead is 8" from the bottom of one 24" tall side panel. I'm still planning the plumbing but at this stage my plan is to not have it go to the sump and go directly to a floor drain. The intention was to use it to make it easier to drain up to 2/3 of the water in the display tank.

My original thought was to just do water changes by draining and filling the display tank.


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## caldwelldaniel26 (Jun 11, 2017)

Okay that sounds like a great idea, I always change out water from the display tank and only remove water from the sump when I'm cleaning the filter.


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## gillmanjr (Jan 27, 2017)

When you start draining your display tank you should keep your return pump running for a minute or two. That will partially drain your sump. Then refill into your display tank and watch as the water starts overflowing into your sump. Fill until your sump is at the very top or close to it. Then when you start your return pump back up mark the line where the water drops to, that is the high water line during pump operation. Keep in mind that you need to have a siphon break or check valve for your return piping in order for this method to work, otherwise you might overflow your sump during a power outage. This worked with my tank because I had a hole drilled right at the water line in my display tank, therefore I didn't have any back siphon into my sump when I shut the pump down.


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## joselepiu (Jul 22, 2017)

gillmanjr said:


> Keep in mind that you need to have a siphon break or check valve for your return piping in order for this method to work, otherwise you might overflow your sump during a power outage. This worked with my tank because I had a hole drilled right at the water line in my display tank, therefore I didn't have any back siphon into my sump when I shut the pump down.


so you need siphon break or check valve on the inlet and also on the outlet of the display tank, right?... :-? :-? :-?


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## caldwelldaniel26 (Jun 11, 2017)

You don't "need" a siphon break on the returns unless they are below the drain line which would make them practically useless for surface agitation and you would have a water fountain spraying out of those holes. Also, you do not need a siphon break on the drain unless you can't run your return reservoir low enough for the sump to contain the water from the display to the low level of the drain. Now if you're running a siphon overflow because your tank isn't drilled, that's a different story but still can be resolved the same way as having standpipes in a drilled tank.


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## zimmy (Aug 13, 2010)

Thanks for the help. I don't plan to use a check valve on the return as it will be very close to the water line. I will drill a hole though as a precaution.


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## joselepiu (Jul 22, 2017)

how do you prevent back-flow on the return to the sump on a power outage?... :-? :-? :-?


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## caldwelldaniel26 (Jun 11, 2017)

You shouldn't need to drill a siphon break if the return is just below the water line. If you feel it's necessary, just make sure the hole is pointing down... I don't know who is burying their return line that far below the water line that it's siphoning enough water to overflow the sump. That's just unheard of to me


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## joselepiu (Jul 22, 2017)

:thumb: :thumb: :thumb: ...


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