Salinity and Two Part Dosing

[fragit]

I've read recently a few posts that have alluded to the fact that using two part dosing for Ca,Alk,Mg adds salt to the system, which is something I never considered in the past when using two part, however I do totally agree with the chemistry of it. So my question is how do we adjust for this in our take maintenance regimes?

 

[Randy Holmes-Farley Verified Community Expert]

I've read recently a few posts that have alluded to the fact that using two part dosing for Ca,Alk,Mg adds salt to the system, which is something I never considered in the past when using two part, however I do totally agree with the chemistry of it. So my question is how do we adjust for this in our take maintenance regimes?

It does slowly add salt over time, and you generally need to remove some to offset it.

For many folks, skimming removes enough and water changes also help correct this, but just monitoring salinity, which you probably do anyway, is the way to go.

If salinity gets higher than you want, just remove some tank water and replace it with RO/DI.

 

[fragit]

It does slowly add salt over time, and you generally need to remove some to offset it.

For many folks, skimming removes enough and water changes also help correct this, but just monitoring salinity, which you probably do anyway, is the way to go.

If salinity gets higher than you want, just remove some tank water and replace it with RO/DI.

That is exactly what I have done in the past, intuitively. I never made the connection between the two part additives being salts, thus raising salinity over time. Thanks for your input Randy!

 

[Randy Holmes-Farley Verified Community Expert]

You're welcome.

Happy Reefing!

 

[James Horst]

Randy, thanks very much for all your help with these questions. I have one more: Would it make sense for me, doing 1%daily continuous water change, to simply mix my replacement saltwater to a lower SG, eg 34.9, rather than add RO/DI? I have been adding RO/DI and removing water as you describe, but wondered about just reducing SG of continuous replacement water.

Also, I assume wet skimming would tend to remove more NaCl than dry skimming?

Thanks again!

 

[Randy Holmes-Farley Verified Community Expert]

That's a fine way to go.

What I actually did in such a seceario is adjust the relative volumes in and out to maintain 35 ppt. That way, the new salt water salinity isn't critical anyway.