Does sodium hydroxide lower salinity?

[DrMMI]

I've been using Randy's recipe for sodium hydroxide as my alk supplement for about 2 months now. However, I noticed that my salinity has been slowly declining. A month ago, my salinity measured 1.026 and now it's 1.024. Even the apex probe shows a gradual decline (I know not to base anything on that, but the decline correlates with my refractometer). The only other things I'm dosing regularly are NoPox and calcium chloride. My ato is still going off regularly and I'm not having to refill it more than usual.

 

[Randy Holmes-Farley Verified Community Expert]

No.

Sodium hydroxide, sodium bicarbonate, and sodium carbonate all have the same impact on salinity for a given alk boost, which is a small increase.

The effect you are seeing is from something else.

 

[Sean Clark]

I would use a different means of measuring salinity and see if you find the same correlation.

 

[Pistondog]

I've been using Randy's recipe for sodium hydroxide as my alk supplement for about 2 months now. However, I noticed that my salinity has been slowly declining. A month ago, my salinity measured 1.026 and now it's 1.024. Even the apex probe shows a gradual decline (I know not to base anything on that, but the decline correlates with my refractometer). The only other things I'm dosing regularly are NoPox and calcium chloride. My ato is still going off regularly and I'm not having to refill it more than usual.

With nopox, you should be running a skimmer, which might be removing salt in the skimmate.

 

[DrMMI]

With nopox, you should be running a skimmer, which might be removing salt in the skimmate.

My skimmate does appear to be a little more watery than it used to be, but volume wise isn't that much more. I'll keep a closer eye on it to make sure that's not the cause. I'm also going to clean my ato pump just to make sure it's not getting stuck on or something.

 

[Randy Holmes-Farley Verified Community Expert]

The salinity measurement may be off, Try recalibrating (or at least checking) it.

 

[LVReefer94]

No.

Sodium hydroxide, sodium bicarbonate, and sodium carbonate all have the same impact on salinity for a given alk boost, which is a small increase.

The effect you are seeing is from something else.

Randy quick question, what sodium hydroxide would you try to source for reef use? I have “100% NAOH” food grade and i think it is actually causing harm to my tank corals have not been happy since its addition.

 

[Randy Holmes-Farley Verified Community Expert]

Randy quick question, what sodium hydroxide would you try to source for reef use? I have “100% NAOH” food grade and i think it is actually causing harm to my tank corals have not been happy since its addition.

What are you observing with the corals?

Food grade sodium hydroxide should be plenty pure enough (as pure as other alk products used), but maybe it's a mislabeled product, maybe you are dosing too fast, or maybe its coincidence.

 

[DrMMI]

So I recalibrated my salinity probe and added in temperature correction. My salinity probe and the manual refractometer both show salinity slowly starting to drop. I'm going to turn off my ato for 24 hours to see if my issue is with too much RO water being added. Checked behind my tank and didn't see any evidence of a leak.

 

[LVReefer94]

What are you observing with the corals?

Food grade sodium hydroxide should be plenty pure enough (as pure as other alk products used), but maybe it's a mislabeled product, maybe you are dosing too fast, or maybe its coincidence.

Could absolutely be coincidence 100% i have not totally factored that out but after 1 full day of its addition everything looked normal and some seemed even better but after day 2 80% of the corals are visibly not happy. Closed up, little to no polyp extention, receding tissue and so on.

 

[Sean Clark]

So I recalibrated my salinity probe and added in temperature correction. My salinity probe and the manual refractometer both show salinity slowly starting to drop. I'm going to turn off my ato for 24 hours to see if my issue is with too much RO water being added. Checked behind my tank and didn't see any evidence of a leak.

Have you used any other methods of salinity measurement?

 

[DrMMI]

Have you used any other methods of salinity measurement?

Not yet. I'm ordering a glass hydrometer since those don't have to be calibrated to see if it shows the same results.

 

[Sean Clark]

Not yet. I'm ordering a glass hydrometer since those don't have to be calibrated to see if it shows the same results.

Redundancy is always a good practice prior to making changes. Great call on the glass hydrometer.

 

[J.V]

Quick questions on adding the sodium hydroxide,
1. Would the one pictured be ok to use, and dosing it through a dosing pump.
2. how much of it to use in a 1 gallon jug to achieve full saturation for max PH benefits.

thank you all!

 

[Randy Holmes-Farley Verified Community Expert]

That one is good.

you will not want to reach saturation. It is super concentrated with a pH way above 14.

Unless there’s a strong reason, use the recommended recipe concentration. The pH effect per unit of alk added is independent of the concentration.

 

[J.V]

@Randy Holmes-Farley
ok really good to know! , would you mind sharing the recipe? Thought it was like kalk, just add to RODI water. Anything else I’m missing? thank you for the lightning fast response and your knowledge btw, very much appreciated

 

[Randy Holmes-Farley Verified Community Expert]

Sure:

Second New DIY Two Part Recipe with Higher pH Boost

In a previous thread, I posted a true two part DIY recipe: https://www.reef2reef.com/threads/new-diy-two-part-recipes-with-higher-ph-boost.344500/ But some folks may want to just swap the new ingredient into my 2/3 part recipe (as used by BRS, for example). Here's the original recipe link...

www.reef2reef.com

 

[J.V]

@Randy Holmes-Farley
Thank you Ordering now