[Rob in (ca)]

For my weekly water change, I mix aerated R/O with The Tap out of the sink.

 

[Higher Thinking]

The benefit would be it will likely drop to a more stable pH level. Most tap water has excess gas in it which causes the pH to be higher than it is normally. If you off gas your water, it will be closer to what you have in your system already. This is of course, completely unnecessary unless you had some very sensitive species and were trying to control parameters.

 

[ngrubich]

The benefit would be it will likely drop to a more stable pH level. Most tap water has excess gas in it which causes the pH to be higher than it is normally. If you off gas your water, it will be closer to what you have in your system already. This is of course, completely unnecessary unless you had some very sensitive species and were trying to control parameters.

In terms of excess gas, it depends on the source of the water. Most of the time, there is come carbon dioxide (well, if dissolved it could be carbonic acid, bicarbonate, or carbonate .... but I digress) that will evolve from the water over time, so the pH will increase to some extent.
You can get around the pH swing by throwing an air stone in whatever is holding the water and let it got for a bit to bubble off the CO2.

 

[Diana]

In winter my tap water has more dissolved gases in it. So much that I lost fish from it.
So I started aerating the water. I use a fountain pump (200-300 gph) in a garbage can. The pump is in the bottom, middle of the can, aimed upward. This creates a strong flume of water that will out gas the excess pretty fast (easily overnight, and a couple of hours seems to be safe). I can also dissolve minerals in this for my hard water tanks, and I add dechlor at this time.

In summer I find a lot less problem with dissolved gases, but I still prep the water this way. The dechlor is well blended, minerals (when needed) are dissolved, and I can prep a lot of water to share among the tanks as needed. It just does not have to be aerated overnight. Half hour is enough, as long as the minerals are dissolved.

 

[jrman83]

If your water is treated locally with chlorine (not chloramine) some do this and not treat their water with a de-chlor. Chlorine will usually dissipate in a few days and aerating helps.

 

[laconic]

If you aerate your water in a storage tank, chlorine will dissipate in 6 hours with no need to add water treatment. If your tap water is treated with chloramine, you will have to use water treatment.