lower salinity issues

[Randy Holmes-Farley]

I had thought the distilled water we buy at the store was a steam distillation, and very pure. Do you not recommend using distilled water for those that don't have an RODI? I've used it at times myself without any issues I knew about. Thank you in advance!

Most large stills likely use stainless steel for condensation, and the metals released will be acceptable in reef use. But I think it is not correct to say it must always be ok since almost no analyses of distilled water for copper have been published.

Here’s one that I found a while ago:

R/O vs. distilled water

If RO is preferable to distilled water, why do entire countries use distilled water instead of RO? Someone else has no idea what an ion is. What can't be trusted is RO water, not distilled water. Your fish store or food store is not obligated by law to change filters and perform other RO...

www.reef2reef.com

 

[Fish Fan]

Most large stills likely use stainless steel for condensation, and the metals released will be acceptable in reef use. But I think it is not correct to say it must always be ok since almost no analyses of distilled water for copper have been published.

Here’s one that I found a while ago:

R/O vs. distilled water

If RO is preferable to distilled water, why do entire countries use distilled water instead of RO? Someone else has no idea what an ion is. What can't be trusted is RO water, not distilled water. Your fish store or food store is not obligated by law to change filters and perform other RO...

www.reef2reef.com

Thank you for your reply!

 

[Uncle99]

Related question from new tanker: I have a 55gal tank on a cannister filter, initial water loaded in 2 months ago, first two fish 1 month ago and nothing since. Parameters are stable. Open screen-covered top, low lights for now. Evaporating about 1/2 gal/day.

I was told the salt doesn’t evaporate so just top off with RODI, which I do. But I’ve noticed twice now my salinity has dropped from 34ppt to 32ppt and I’ve had to add saltwater / water change to bring it up.

Is this normal? What causes salinity to go down? Just trying to learn what’s normal and what’s a problem.
Thanks!

Use an ATO to ensure accuracy in salinity due to evaporation

 

[dippy-bird]

Related question from new tanker: I have a 55gal tank on a cannister filter, initial water loaded in 2 months ago, first two fish 1 month ago and nothing since. Parameters are stable. Open screen-covered top, low lights for now. Evaporating about 1/2 gal/day.

I was told the salt doesn’t evaporate so just top off with RODI, which I do. But I’ve noticed twice now my salinity has dropped from 34ppt to 32ppt and I’ve had to add saltwater / water change to bring it up.

Is this normal? What causes salinity to go down? Just trying to learn what’s normal and what’s a problem.
Thanks!

(Maybe not really relevant for a 55gal tank) -
If you are running a skimmer and you are running it wet you export a significant amount of saltwater out of the tank, with a ATO you refill it with RODI water and your salinity can drop over time

 

[MNscoe]

Good questions. I haven’t been that precise so far. I add 0.25 - 0.5 gallons of RODI each morning. I have a spot on the rim I kinda eyeball for consistent water level.

I measure salinity before adding new RODI. Using an Aqualife Pro.

Well, dangnabbit, turns out my salinity tester was going out of calibration. I went to do a water change and was adding salt, and when I added a bit more salt my test readings went DOWN. As a newbie, that was the first time I realized you need to calibrate (and monitor the calibration of) the Aqualife Pro tester! Dang.

Therefore when I thought my tank salinity was going down, and I starting using saltwater to top it off, I was actually increasing salinity to about 38ppm. Oops! Fixed now.