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View Full Version : Why age seawater mix?


ArtC
10/04/2009, 01:02 PM
I've seen a lot of people talk about letting their seawater age for days before using it, but none of them have mentioned why. Are there chemical reasons, or is it just for luck?

I normally store my RO/DI water as is, and mix salt when I need it. (It being somewhat easier to turn fresh into salt than the other way around!) My assumption was that I'd get O2/CO2 equilibrium either way, but do the dissolved gasses get consumed in the salt mixing process?

HighlandReefer
10/04/2009, 02:38 PM
I have added salt mix batches just a few minutes after mixing and have let it age for weeks before adding it. I have never seen any significant effect on the pH of my DT after adding the batches either way.

In many cases the rodi water is stored with a lid on it, which can reduce the amount of CO2 that will dissolve in the rodi water. This will make the pH of newly mixed water higher. When this mix is added to the DT, the CO2 level will equilibrate fairly quickly.

harper
10/04/2009, 04:35 PM
Some of the salts I have used have a brown settlement after a day or so (IO, RC, OceanPure, D&D). These mixes will be clear when first mixed. Just figured it would be better not to add this junk to the aquarium. I do a water change then make up the water for the next one and let it sit. It also gives me a backup of instant saltwater if something should arise... D&D has a FAQ about the brown clay that it is easy to skim out, and it ties up phosphates.

bertoni
10/04/2009, 06:46 PM
Some salt products mix up to an initial high pH, and require some aeration to reach a normal pH. That's a good reason to wait before using. :) Waiting longer might allow bacteria to process the trace amounts of ammonia in the system, I guess.

Okayamapiper
10/04/2009, 07:08 PM
Another reason is that dechlorinators in the mix lower oxygen levels in the new water and need time to return to normal.

Boomer
10/04/2009, 07:22 PM
There is not need to wait or age it longer than 24- 48 hrs, via good circulation with an air stone or PH. If you mix it with a large paint stirrer on a drill you are set, ready to go in 5 min of mixing