Aging RO/DI water

Joined
9 Sep 2014
Posts
238
Reaction score
8
Location
Vaal Triangle
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 don't think its necessary, wouldnt that change the salinity because of evaporation?
Just let it mix and let the salt dissolve and you should be good to go:thumbup:
 
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
 
The water i buy from the LFS usually stand for more than a week before being used. Never had a problem.
 
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 .
 
As for new salt mix. Some brands can be used within minimal time...2hrs. I prefer a day or so.
 
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

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.
 
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 .

Apart from the buffering capacity, the pH is normally low due to the excessive dissolved CO2

So RO water is not necessary "pH neutral" pH7, if pH7 is considered neutral. The pH of RO water can drop to the higher pH5's and lower pH6's.

Wonder how many reefers know what the pH of their RO water is? or if it makes a difference?
 
Last edited:
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.


Yip agree , many brands are somewhat vague though. Tropic Marin only recommends mixing untill the solution is clear. Red Sea recommends using it virtually straight away . Several salt brands to have small amounts of ammonia as a contaminant from the Solvay process used to make calcium chloride. I''ve never detected in Tropic Marin or Red Sea Coral Pro though.
 
Last edited:
Yep, the ph of Ro /Di can change in seconds. That is why you actually buffer distilled water with KCL before measuring the ph. How to Measure the pH of pure water

Btw who remembers their first chemistry test in school ? Saturated limewater, a straw and the co2 from breathing..
 
Last edited:
Back
Top Bottom