# Do I need to dechlorinate water before mix with RO?



## wilamzq (23 Nov 2019)

Hey,

As the title indicates I would like to mix my RO water with some tap water (75/25) to increase KH a bit more so and I am wondering, Do I have to dechlorinate the tap water before mix it with the RO?

Thank you


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## Parablennius (23 Nov 2019)

Does your tap water have Chloramine or free Chlorine? My supply has free Chlorine which gasses off. As such I prepare my change-water, 40% ish ( Heat, adjust GH etc) the day before and use it the next day untreated. Chloramine, of course, will need pre-treating.


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## GlenD (23 Nov 2019)

Hi, no. Mix RO/tap together and then dechlorinate.. Is what i do


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## wilamzq (23 Nov 2019)

Parablennius said:


> Does your tap water have Chloramine or free Chlorine? My supply has free Chlorine which gasses off. As such I prepare my change-water, 40% ish ( Heat, adjust GH etc) the day before and use it the next day untreated. Chloramine, of course, will need pre-treating.



According to my water provider parameters we have ( Total Chlorine 0.2 ppm, Chloride (Cl-) 20, NH4 0.01 ) and doesn't mention anything for Chloramine or Chlorine..


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## Parablennius (23 Nov 2019)

Chloramine is deliberately aimed at "hanging around longer". Utilities supply us with drinking quality water, not fishkeeping water.  Can't you do what I did, speak to your supplier directly, ask the question?


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## GlenD (23 Nov 2019)

The problem with not adding Prime etc., is if your local water supplier begins to add chloramine into the tapwater you could end up killing your fish before you find out.


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