Should i be aging my ro/di water or not. Someone once told me that its better to mix my salt into new RO water one week in advance, and let the saltwater age for one week.... Anyone with any opinions on the matter?
I think why they say you need to do it one week in advance is to let the ph stabalize but most salts you can mix and put in straight after mixing
Nope, not neccssary . We used to age tap water to allow the chlorine to dissipate. Your carbon cartridges took care of that Pure (ro/di ) water has no buffering capacity and is therefore ph unstable .
I have seen some salt brands claim that one can mix and use immediately but I advise not to.
You are correct that the pH needs to stabilize, but there are other important factors that influence the timeline of parameters after mixing. Apart from allowing the many "chemical" elements and reactions to take place the biggest one is the mg. High magnesium salts, when first mixed, create ammonia due to the chemical reaction. This results in a big loss of DO in the mix. That is why it is recommended to aerate the mix for 24 hours by most reputable brands.
Salt water can be stored for reasonable periods or time. Most parameters will remain unchanged. However where and how it is stored can be an issue. Similar to RO water storage.
RO water is very different and more aggressive. RO/DI water will absorb any particles and gasses that is in the atmosphere or that it comes into contact with. So containers need to be sealed, clean and free of algae spores. Also it is advisable to keep out of light.