RO water that passes through softener first

[pixlweaver]

Hello!

Would it be bad to use RO water that has passed through a water softener first? Water softener is salt based Rainsoft system. I'm thinking about how to lower the hardness of the unsoftened tap water I'm using in our aquarium. The test strips I use show hardness as bright purple, 300ppm +. I just ordered the API GH test kit to see if that's more accurate. Our city's water quality report from last year claims 181 for calcium hardness, 260ppm for total dissolved solids.

If it's safe, I plan to mix in some of the RO water with the tap water during water changes.

[flyingcow]

On 10/13/2022 at 3:17 PM, pixlweaver said:

Hello!

Would it be bad to use RO water that has passed through a water softener first? Water softener is salt based Rainsoft system. I'm thinking about how to lower the hardness of the unsoftened tap water I'm using in our aquarium. The test strips I use show hardness as bright purple, 300ppm +. I just ordered the API GH test kit to see if that's more accurate. Our city's water quality report from last year claims 181 for calcium hardness, 260ppm for total dissolved solids.

If it's safe, I plan to mix in some of the RO water with the tap water during water changes.

A DI cartridge after the RO should do the trick to get out the remaining sodium.

[pixlweaver]

On 10/13/2022 at 2:53 PM, flyingcow said:

A DI cartridge after the RO should do the trick to get out the remaining sodium.

So it would not be safe to use the RO water as is? This RO system is our drinking water, so I wouldn't want to mess with it by adding a cartridge. Nor do I have any experience with plumbing... or aquariums for that matter. Also definitely don't have space under the sink, since the RO system has 3 cartridges and a tank under there.

If it's not safe to use, then my other options is distilled water or adding chemicals, is that correct?

[flyingcow]

On 10/14/2022 at 12:09 PM, pixlweaver said:

So it would not be safe to use the RO water as is? This RO system is our drinking water, so I wouldn't want to mess with it by adding a cartridge. Nor do I have any experience with plumbing... or aquariums for that matter. Also definitely don't have space under the sink, since the RO system has 3 cartridges and a tank under there.

If it's not safe to use, then my other options is distilled water or adding chemicals, is that correct?

So first off, if you're measured hardness and the water report vary that drastically, I'd try a different test kit to make sure it isn't that hard. GH and KH are two tests where I think the API liquid test kits are worth it over a strip.

The small amount of sodium remaining after a softener and RO may or may not have an impact on the aquarium (especially plants, I believe, but people can feel free to correct me on that one). If you reduce hardness by mixing water from before the softener/RO and water from after, you'll get softer water, and any remaining sodium from the softener will be diluted and less likely to give an issue.

 

[pixlweaver]

On 10/14/2022 at 11:45 AM, flyingcow said:

So first off, if you're measured hardness and the water report vary that drastically, I'd try a different test kit to make sure it isn't that hard. GH and KH are two tests where I think the API liquid test kits are worth it over a strip.

The small amount of sodium remaining after a softener and RO may or may not have an impact on the aquarium (especially plants, I believe, but people can feel free to correct me on that one). If you reduce hardness by mixing water from before the softener/RO and water from after, you'll get softer water, and any remaining sodium from the softener will be diluted and less likely to give an issue.

 

Ok thanks so much for your advice! The API test should arrive today or tomorrow so very curious to see what it says.

 

[lefty o]

a water softener puts in so little salt to start with, then you are running it through an RO system, its nuts to even think about it at that point.

[flyingcow]

On 10/14/2022 at 3:55 PM, lefty o said:

a water softener puts in so little salt to start with, then you are running it through an RO system, its nuts to even think about it at that point.

It puts in as much sodium as it takes out calcium.

[lefty o]

yup, its not much even in very hard water.