Live Aquaria salt

[Origami]

OK, the two different salts confused me (e.g. 1/4 cup iodized and 1 tsp "salt").

Ha. I never noticed that. Basically, Randy's calling out Morton's because of the standard grain size and because that's the one that he weighed out to get an average weight. In the end it's the weight of the salt and the water that's important here, so grain size and shape will make a difference (e.g. a quarter cup of rock salt will probably weigh different than a quarter cup of table salt). The iodine content won't make much difference because it's not at a significant enough concentration to have a noticeable effect. He's adding that extra teaspoon to get the salt mass up to just beyond 79 grams. He's having the person make so much so as to dilute the effect of measuring errors.

[madweazl]

Maybe it's not the calibration solution, then. You may want to quickly mix up some of the DIY solution just to confirm that you're in the ballpark. If you don't have a Coke bottle, then I think that 1 Tbsp. of salt into 2 cups plus 4 teaspoons of RO/DI or distilled water will put you right at about 35 ppt.

 

It's almost assuredly crazy to ask since it sounds like you're doing it all right, but you're mixing this new salt up in RO/DI or distilled water, right? No worries about extra calcium and (bi)carbonates (hardness) in tap water?

 

Alan, you started this thread. Have you mixed any of this new salt up yet?

This solution came out to a hair under 1.027 (high side of 35ppt on my refractometer) and the calibration solution I had purchased was right at 1.026 this afternoon and confirmed again right after I tested the recipe above. 

 

Edit: On another note, I finished the water change about two hours ago and polyp extension on the SPS has been fantastic the last hour (a couple shot out mesenterial filaments). 

Edited October 12, 2017 by madweazl

[Origami]

This solution came out to a hair under 1.027 (high side of 35ppt on my refractometer) and the calibration solution I had purchased was right at 1.026 this afternoon and confirmed again right after I tested the recipe above. 

Sounds like it's the salt mix, then, that's mixing up really high. Not a great start. They've got to get quality under control or the launch will be soft at best as people decide "it's not the salt for me."

 

I'm interested in hearing how others are faring with their samples. 

[AlanM]

I’ll mix up some tonight to test it. I’ll make sure to agitate the bag to distribute any variances before opening so as not to make a mess. I just calibrated my refractometer with the same solution madweazl is using to calibrate his.

[madweazl]

Lot #30624 for the bag I have. 

[AlanM]

Lot #30624 for the bag I have. 

Same lot for me. So far same experience as you. Ten minutes after mix and still cloudy but clearing up.

[AlanM]

I vastly overshot. Never mixed just 1 liter before. Tested SG at higher than 100 ppt. Starting over in case dilution will affect results.

[tygger]

Interesting point about the calibration fluid. I'm using the Aqua Craft solution too.

[madweazl]

I vastly overshot. Never mixed just 1 liter before. Tested SG at higher than 100 ppt. Starting over in case dilution will affect results.

Should take about 1/8 cup. 

[AlanM]

OK.  Here's the results,  you aren't gonna like it.

 

Ca: 420

Mg:1280

dKh: 7.4 (133ppm)

SG: 35ppt

 

I can't explain why mine are so different.  I'm not surprised that the alk could vary a bit based on the source water's CO2 content.  The others seem like they should be pretty consistent.

[AlanM]

SG:

 

 

Alk:

 

 

Mg:

 

 

Ca: (used .84 to get to this color, forgot to take pic of syringe)

 

[madweazl]

OK.  Here's the results,  you aren't gonna like it.

 

Ca: 420

Mg:1280

dKh: 7.4 (133ppm)

SG: 35ppt

 

I can't explain why mine are so different.  I'm not surprised that the alk could vary a bit based on the source water's CO2 content.  The others seem like they should be pretty consistent.

CO2 doesnt have an effect on alkalinity so that wouldn't matter. Certainly interesting that our results were so much different from the same lot. I was hoping to get levels around what you got LOL. 

[AlanM]

I don't know for sure what the Hanna alk checker reagent does, so I assumed CO2 content could throw off the measured result if it's actually measuring pH somehow.  /shrug  I know CO2 wouldn't affect the true alkalinity.  My alk reagent expired in July, by the way, but I have still been using it on my tank and I got two consistent 133ppm readings in a row.

 

I'll measure it again tomorrow with a newly mixed sample from a different part of the bag.  After doing the test I read the bag again and saw that they say to wait 2-4 hours before using to allow the solution to equalize.  I just tested as soon as it mixed clear (which it did after about 10 minutes, like you saw).  Tomorrow I'll mix in the morning and test at lunch.

[madweazl]

I don't know for sure what the Hanna alk checker reagent does, so I assumed CO2 content could throw off the measured result if it's actually measuring pH somehow.  /shrug  I know CO2 wouldn't affect the true alkalinity.  My alk reagent expired in July, by the way, but I have still been using it on my tank and I got two consistent 133ppm readings in a row.

 

I'll measure it again tomorrow with a newly mixed sample from a different part of the bag.  After doing the test I read the bag again and saw that they say to wait 2-4 hours before using to allow the solution to equalize.  I just tested as soon as it mixed clear (which it did after about 10 minutes, like you saw).  Tomorrow I'll mix in the morning and test at lunch.

Ah, no clue on the Hanna checker in that regard (they're all magic in my mind). I didn't test the same bucket but the results were pretty consistent between the two; the first I tested about an hour after mixing and the other was 24+ hours later so I wouldn't expect to see much of a difference. 

[madweazl]

Would you be willing to test a batch of mine if I ship you some of the salt? 

[AlanM]

Sure.  I'd do that.   I'm really curious now.  I'll also send you some of mine.  

[Origami]

On CO2 and alkalinity:

 

Dissolved CO2 forms carbonic acid, H2CO3. It dissociates to yield a hydrogen ion (proton) and a bicarbonate ion:

 

H2CO3 ==>> H+ + HCO3-

 

You see where this is going? Even though carbonic acid is acidic and should neutralize a base, for every hydrogen that neutralizes an ion of carbonate alkalinity, another is freed. So there is no change in alkalinity from dissolved CO2.

 

Sent from my SM-G930V using Tapatalk

[madweazl]

On CO2 and alkalinity:

 

Dissolved CO2 forms carbonic acid, H2CO3. It dissociates to yield a hydrogen ion (proton) and a bicarbonate ion:

 

H2CO3 ==>> H+ + HCO3-

 

You see where this is going? Even though carbonic acid is acidic and should neutralize a base, for every hydrogen that neutralizes an ion of carbonate alkalinity, another is freed. So there is no change in alkalinity from dissolved CO2.

 

Sent from my SM-G930V using Tapatalk

 

 

All I see is voodoo!  

Edited October 12, 2017 by madweazl

[Origami]

All I see is voodoo!

Yeah, right?

 

It's like - if alkalinity was a red poker chip and acid was a black one, then adding CO2 would be like adding a black chip PLUS a red one. The red chips still have the same net advantage and alkalinity doesn't change.

 

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[AlanM]

Tom, check out Dana Riddle's old article on Hanna checkers.  They measure pH using an indicator so I assume they are always a bit off.  I'm sure they make assumptions about the amount of CO2 in your water when figuring ppm since they're not doing a titration and finding the end point.

 

http://www.advancedaquarist.com/2011/8/review

[Origami]

Tom, check out Dana Riddle's old article on Hanna checkers.  They measure pH using an indicator so I assume they are always a bit off.  I'm sure they make assumptions about the amount of CO2 in your water when figuring ppm since they're not doing a titration and finding the end point.

 

http://www.advancedaquarist.com/2011/8/review

Yes, most (if not all) colorimeters (I suspect) use a pH model to estimate the titration end point to determine alkalinity. After all, a measurement of alkalinity is, by definition, the ability to neutralize an acid.

 

See above. Dissolved CO2 is not a factor in your tank's alkalinity. Dissolved CO2 introduces a unit of carbonate alkalinity for every unit of acid that it also introduces. Thus, the net effect on alkalinity is zero.

[AlanM]

I don't know for sure what the Hanna alk checker reagent does, so I assumed CO2 content could throw off the measured result if it's actually measuring pH somehow.  /shrug  I know CO2 wouldn't affect the true alkalinity.  

 

Tom, I know CO2 wouldn't affect the true alkalinity.  I am pretty sure it will affect the measured alkalinity number displayed on the Hanna checker, though.

[Origami]

Tom, I know CO2 wouldn't affect the true alkalinity.  I am pretty sure it will affect the measured alkalinity number displayed on the Hanna checker, though.

 

 

I see what you're saying. Yes, but all colorimetric test kits implement a model that projects a pH end point as the basis for their alkalinity estimate. That model, though, assumes that carbonate species are in equilibrium. 

 

So, 

 

1) CO2 has no effect on alkalinity, but

2) CO2 can affect alkalinity measurement because, what we're using to estimate alkalinity is often times really an estimation to a pH titration endpoint.

 

That's probably why we want to measure at the same time every day (to stabilize those variations).

 

Here's a good thread from RC from 2012. Some big names in there... Randy Holmes-Farley, Habib (from Salifert), and Chris Jury.

 

http://www.reefcentral.com/forums/showthread.php?t=2130613

[madweazl]

In reading the thread, the endpoint pH doesn't seem to matter a whole lot, correct?

[AlanM]

So I'm not a chemist, but I don't think the actual pH number matters if you're doing a titration test using an acid and a pH probe.  This is what those automated alk testers do. 

 

I believe the raw number doesn't matter, just the point at which the curve changes.  Basically the point at which all carbonate is used up by the acid if I'm remembering it correctly.

 

The pH of the solution should matter when doing a color test for alkalinity with an indicator chemical, though.