Alkalinity will not increase. I'm stumped.

[Scubabum]

Wanted to run something by everyone. I have a very strange situation that I've never seen or experienced before. I have a 65 gallon batch of saltwater mixing right now. It's pretty low in alkalinity. 6.2 dkh. I have been trying to buffer it up for 2 days now with BRS soda ash. I have added over 200ml of Mixed soda ash and I can't seem to increase alkalinity. Never experienced anything like this before. Mag is testing at 1400 and calcium at 440ppm. I have tried 2 seperate Hanna alk testers with 2 different lot number reagents. I'm stumped on this. Any thoughts or has anyone ever seen anything like this? Hoping someone may know what might be causing this. Thanks in advance. Enjoy the rest of your weekend. Phil

 

[Sebastiancrab]

Could your soda ash be bad?

 

[Scubabum]

Could your soda ash be bad?

I was thinking that but I've been using it to dose my frag tank which has pretty steady dkh. I think I have another bag. I'll try that next. Thanks for the suggestion.

 

[Sebastiancrab]

It's either that or your test reagents are bad. I use BRS sodium bicarbonate liquid mixed up.

 

[Scubabum]

Follow up. It appears my Soda Ash is bad or reacting in some type of chemical way. I used AquaForest KH buffer and it raised alkalinity exactly where I wanted it.

 

[reefiniteasy]

Follow up. It appears my Soda Ash is bad or reacting in some type of chemical way. I used AquaForest KH buffer and it raised alkalinity exactly where I wanted it.

The fact that you were adding and nothing was happening and it might have been causing a reaction, is the batch of water ok to use? Just wanted to pose the question in case it’s not. @Randy Holmes-Farley any insight?

 

[Scubabum]

The fact that you were adding and nothing was happening and it might have been causing a reaction, is the batch of water ok to use? Just wanted to pose the question in case it’s not. @Randy Holmes-Farley any insight?

Great Question!!!! I'll wait to use, until I hear from someone that knows chemistry and if this might cause an issue. I'd rather dump 65 gallons than risk my livestock.

 

[Dennis Cartier]

Just speculating on what might have been happening. If the Soda Ash was raising the PH high enough, it might have been precipitating out. The AquaForest KH buffer does not say what it is made of, but I suspect it uses sodium bicarbonate, which would not raise PH, and would possibly lower it a bit. That would explain why it worked, while the sodium carbonate (soda ash), did not.

Dennis

 

[Scubabum]

Just speculating on what might have been happening. If the Soda Ash was raising the PH high enough, it might have been precipitating out. The AquaForest KH buffer does not say what it is made of, but I suspect it uses sodium bicarbonate, which would not raise PH, and would possibly lower it a bit. That would explain why it worked, while the sodium carbonate (soda ash), did not.

Dennis

Thanks Dennis. I thought of that, so I was testing the PH and the highest I saw it go was 8.6 PH. I'm not sure if that's high enough to cause that or if it spiked even higher, but the highest I observed it was 8.6

 

[Spare time]

Sounds like precipitation. Soda ash has to be added slowly, otherwise you can dose a ton and seemingly not bump up the alkalinity. I have part of a sand bed that turned into a solid cave system from this when I first tried pure soda ash haha.

 

[taricha]

If I got a weird result with a hanna alk kit, I'd really want to check it with a plain old titration kit.
(Though it seems high pH precipitation is answering your question)

 

[Randy Holmes-Farley Verified Community Expert]

You added way too much soda ash. It will boost alk by 4.3 dKH (maybe you wanted that, but no, DO NOT DO IT). You boosted pH by a huge factor (1.4 dKH added this way boosts ph by 0.35 pH units), which likely precipitated out a lot of calcium carbonate.

Raw salt water is very prone to precipitation (much more so than aquarium water) ,a nd high pH alk additives are definitely not the best way to raise the alk.

If you need to raise alk in a salt mix, baking soda is the easiest way.

 

[reefiniteasy]

You added way too much soda ash. It will boost alk by 4.3 dKH (maybe you wanted that, but no, DO NOT DO IT). You boosted pH by a huge factor (1.4 dKH added this way boosts ph by 0.35 pH units), which likely precipitated out a lot of calcium carbonate.

Raw salt water is very prone to precipitation (much more so than aquarium water) ,a nd high pH alk additives are definitely not the best way to raise the alk.

If you need to raise alk in a salt mix, baking soda is the easiest way.

Is it best to scrap the batch of water?

 

[Randy Holmes-Farley Verified Community Expert]

Is it best to scrap the batch of water?

For 65 gallons, I'd let it settle clear, measure the calcium, dose it up to 420 ppm if needed, check the alk, and use it.

With solid white ppt of calcium carbonate in the barrel (do you see any?), it will be even more prone to precipitation, so I would not boost this batch even with baking soda.

 

[Scubabum]

For 65 gallons, I'd let it settle clear, measure the calcium, dose it up to 420 ppm if needed, check the alk, and use it.

With solid white ppt of calcium carbonate in the barrel (do you see any?), it will be even more prone to precipitation, so I would not boost this batch even with baking soda.

Thanks for the info Randy! I realized I made a mistake by using Soda Ash. I didn't dose it all in one shot, but regardless I see my mistake and understand now why it wasn't working. There isn't any solid white residue. I checked the Calcium but will double check it before using. Alk is finally where it needs to be. I used Sodium Bicarbonate last night before you responded to this thread using the recommendation that others suggested. Appreciate the info.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks for the info Randy! I realized I made a mistake by using Soda Ash. I didn't dose it all in one shot, but regardless I see my mistake and understand now why it wasn't working. There isn't any solid white residue. I checked the Calcium but will double check it before using. Alk is finally where it needs to be. I used Sodium Bicarbonate last night before you responded to this thread using the recommendation that others suggested. Appreciate the info.

That sounds good.

Happy reefing.