RO/DI Water Question

[tonytran509]

So i have a question, I made some RO/DI water and had like 5 gallons left sitting, tested with my TDS meter and with the one on the unit itself says its 0... i let it sit for 2 days and then its at 16..... so is this normal? or am i suppose to do something to avoid this?

Thank you,
Tony

 

[Doberman13]

What kind of container was it left sitting in? I've heard that any type of container that was used for other things before can leach TDS into your water.

 

[dball711]

Was the container covered, that can make a difference.

 

[bhodges82]

Also could have picked up debris on the water surface if it was not circulating.

 

[tonytran509]

@Doberman13 3 it was sitting in a home depot bucket that i only use for water... could it happen if i previously used it for tap water for my fresh tanks?
@dball711 the one from today was not covered and the other one from last week was covered but both did the same thing
@bhodges82 its just sitting water not pumps to circulate water....

 

[sharis100]

So i have a question, I made some RO/DI water and had like 5 gallons left sitting, tested with my TDS meter and with the one on the unit itself says its 0... i let it sit for 2 days and then its at 16..... so is this normal? or am i suppose to do something to avoid this?


Are you using the HDPE food safe buckets for storage? The other buckets leach over time.

 

[ichthyoid]

CO2 readily dissolves in DI water. Once in solution it spontaneously ionizes and forms carbonic acid, a source of H+ ions. A conductivity meter is used to measure the content of TDS and will detect such ions as an increase in TDS. Keeping the DI container sealed will help prevent the change.

https://education.ti.com/~/media/029608482684423FAD45D941FEAD5B99

 

[Doberman13]

CO2 readily dissolves in DI water. Once in solution it spontaneously ionizes and forms carbonic acid, a source of H+ ions. A conductivity meter is used to measure the content of TDS and will detect such ions as an increase in TDS. Keeping the DI container sealed will help prevent the change.

https://education.ti.com/~/media/029608482684423FAD45D941FEAD5B99

Does this increase in TDS from H+ ions have any cause for concern for reef tanks?

 

[ichthyoid]

I’ve never worried about it. When you mix salt the acidity is reacted along with everything else and the buffers balance out the pH.

FWIW,
The same CO2 from the air is what causes tank pH to drop at night after lights go off & photosynthesis stops. The photosynthesis from algae, coralline or otherwise, provides bicarbonate as a byproduct. This is also why some people install CO2 scrubbers on the airline feeding their skimmers.

 

[tonytran509]

I’ve never worried about it. When you mix salt the acidity is reacted along with everything else and the buffers balance out the pH.

FWIW,
The same CO2 from the air is what causes tank pH to drop at night after lights go off & photosynthesis stops. The photosynthesis from algae, coralline or otherwise, provides bicarbonate as a byproduct. This is also why some people install CO2 scrubbers on the airline feeding their skimmers.

but what if i was using the water for an ATO should i be worried then?

 

[dball711]

Keeping the DI container sealed will help prevent the change.

https://education.ti.com/~/media/029608482684423FAD45D941FEAD5B99

+1 this.

 

[ichthyoid]

but what if i was using the water for an ATO should i be worried then?

I wouldn’t. The CO2 will eventually be in equilibrium with your tank’s water, no matter what you do.

The pH & alkalinity will stabilize, and be influenced by which dosing method you choose (2 part, calcium reactor, etc.).

This is one of the main reasons why people may tell you not to chase numbers.

 

[tonytran509]

I wouldn’t. The CO2 will eventually be in equilibrium with your tank’s water, no matter what you do.

The pH & alkalinity will stabilize, and be influenced by which dosing method you choose (2 part, calcium reactor, etc.).

This is one of the main reasons why people may tell you not to chase numbers.

thank you for the info that helps me figure things out a lot.... yeah everyone been telling me to not chase numbers....just gotta keep that in the head lol