Water change - simultaneous pump in/out

Does anyone do water changes using a simultaneous pump in/out method? Basically what I want to do is simultaneously pump out where water enters my sump and pump in into my return section.

I'll figure out how much I need to do for a certain percentage water change (it requires some calculus), but I just wondered if anyone does this.

-Clayton

 

I wouldent because your not removing the maxium amount of water. By doing it that way you removing new water as well. I bet if you do it both ways and test nitrite after both changes you will see for your self.

 

I do that on one of my tanks. I use a two siphon / two container method.

Stand both containers, one on top of the other, next to the tank. Top container is full of fresh mixed water, and bottom container is empty. Run one siphon from the top container into the sump. Run a second siphon from the outlet weir section of the main tank into the bottom container. Prime both siphons, and let her run. The fresh water empties into the sump and the dirty water is removed from the weir section. Takes about 3 minutes to do a 15% water change.

Any more than that though and the fresh water will be making its way into the weir section.

 

Yes I am in the process of setting up an automated water change system which involves simultaneous in/out pump technique. I am planning on 1 to 2 percent daily over 24 hour period each day. Exactly as you suggested, draw from the sump's inlet and input fresh on the sump's outlet. You'll need a very accurate pump for metering. I use Spectra's liter meter pumps for this.

 

Yes I know I'm not maximizing the water change potential. I'm looking at it to ease water changes. I can do them at the sump and not even have to shut anything off. That's more important to me than getting the maximum value out of the water.

Also, the way I'm planning it flow wise, it should be wasting very little water as long as I'm not doing a large change (allowing more time for the old and new water to mix.)

I like plandy's idea of automating it, so I'll be looking into that. Thanks everyone.

 

Use a bucket with an overflow, pumps out of the sump and fills the bucket which in turn overflows back to the sump.This would be the same way as your tank runs

 

I do mine with a pump matching my return pump I take the return from my sump and put it in one empty 32 gallon Brute can and I have a full 32 gallon can next to the tank I hang the new water inlet opposite my overflowbox pointing down and I turn both pumps on at the same time The water is flowing in at the same rate I am pumping it out . This is really fast and easy I am done in 5 minutes with a 32 gallon change . Also by keeping the spare exact match return pump I have a spare if my main return pump goes.

 

If everyone doing this is doing it so they don't have to turn off the return pump or something, I don't see real benefit to it. You are pumping good water in and more than likely (as hack said) you are pumping good water back out. When taking out existing tank water first you are assured of removing "spent" water and replacing it with pure.