Water Change - how do you siphon out EXACTLY as much as you are putting back in?

[Reeflier]

On initial tank setup, even before adding salt, with all pumps off I drain/siphon as much as I want to remove each water change into whatever vessel I will be mixing new salt water in. I make a mark with a sharpie on the salt mix vessel, as well as unobtrusively on the display tank. When I do water changes I mix up new water to the sharpie line in the mix vessel, and then (again with all pumps off) drain off the display tank to the sharpie line (I siphon directly into the house drain system each water change). Since it was previously measured, the amount removed from the display tank exactly matches the amount mixed up and added back to the tank. This, of course can be done well after initial tank setup. However, it's just easier to play with fresh water in case mistakes are made and you have to start over, and your also doing it not worrying about keeping corals out of the water too long, etc. If you want to start using this method after initial setup, plan ahead and work steady and it should go fast enough to not cause concern.

 

[Mikeltee]

No, I normally add more than I sipon out and let it overflow over the sides of my tank. Seriously?

 

[GK3]

I always seem to drain more than I put back in and this causes my ATO to run and I'm worried if will throw off salinity because of it. How are you guys changing water such that your ATO doesn't run once you are done?

I have both a saltwater and freshwater fill connected to my tank. When I do a water change I turn off the normal ATO (fresh), siphon out the water, then turn On the saltwater fill in which is connected to the same sensor as my normal ATO. When it shuts off I know it’s back to exactly where it was and I switch back to the fresh ATO.

 

[Mikeltee]

Empty into 5 gallon bucket and replace with the same amount. You can also keep a line with your water level in your sump. Its obviously important that you are precise. Too much addition and your salinity will be high and vice versa.

 

[Jhav89]

Two brute trash cans. I use the indentations as a reference and drain my system enough to match the water line on the fresh batch. I will switch over to AWC eventually

 

[sick.boy]

I have 2 containers exactly the same size. Fill one with dirty water from the aquarium or sump and one with fresh water. Never goes wrong,

 

[corey904]

I always seem to drain more than I put back in and this causes my ATO to run and I'm worried if will throw off salinity because of it. How are you guys changing water such that your ATO doesn't run once you are done?

I use an auto aqua Awc/Ato and it’s made my water change system so easy I would definitely recommend the product

 

[silvernblackr35]

I use identical containers for freshly mixed water that way you just match the water level of what you are taking out with the water level in the fresh mix.

 

[D E N I N O]

I've got all my containers marked up with lines every 10 litres.

Takes a few minutes to do, I just use a bucket and pour in 10 litres, draw a line and move to the next one.

 

[91yjeeper]

I use an auto aqua Awc/Ato and it’s made my water change system so easy I would definitely recommend the product

Not a bad idea! Thanks.