Dumb question about NaOH dosing

[reely989]

So when adding hydroxide I know some cloudiness and precipitation occurs. I have a power head aimed at the dosing spot to mix it. I guess my question is if it all doesn't get mixed back on does that make the dose less effective? On other words-- is what precipitates out preventing the full alkalinity boosting effect from occuring?

 

[Randy Holmes-Farley Verified Community Expert]

If undissolved solids remain well after dosing, then yes, it is depleting alk and calcium or magnesium or both.

 

[reely989]

If undissolved solids remain well after dosing, then yes, it is depleting alk and calcium or magnesium or both.

In that case the answer is just dosing into a higher flow area, right?

 

[Randy Holmes-Farley Verified Community Expert]

In that case the answer is just dosing into a higher flow area, right?

Typically, dosing hydroxide is trickier than carbonate which is trickier than bicarbonate, and the higher the flow the better. :)

Diluting it so it is dosed more slowly can also help.

 

[reely989]

Typically, dosing hydroxide is trickier than carbonate which is trickier than bicarbonate, and the higher the flow the better. :)

Diluting it so it is dosed more slowly can also help.

I gotcha. I'm mixing it at a pretty concentrated solution so I don't have to keep as much on hand. I guess I'm curious because I started running a CO2 scrubber, which has raised my pH. At the same time I've seen a dip in my alkalinity and I'm not convinced my consumption has increased that much. I'm wondering if the increased pH has made it precipitate more and not mix into the water as well. Guess I'll have to do some investigating.

 

[Randy Holmes-Farley Verified Community Expert]

I gotcha. I'm mixing it at a pretty concentrated solution so I don't have to keep as much on hand. I guess I'm curious because I started running a CO2 scrubber, which has raised my pH. At the same time I've seen a dip in my alkalinity and I'm not convinced my consumption has increased that much. I'm wondering if the increased pH has made it precipitate more and not mix into the water as well. Guess I'll have to do some investigating.

If it is more concentrated than my recipe, I'd reduce it. :)

Raising pH does raise demand for alk.

 

[reely989]

If it is more concentrated than my recipe, I'd reduce it. :)

Raising pH does raise demand for alk.

Yeah, I'm mixing it at 1.5x what your recipe is. I'll have to mess around with it. Might not be an issue. My alk demand might have increased, I guess I'm just skeptical that it would increase much in a day or two lol

 

[Randy Holmes-Farley Verified Community Expert]

Yeah, I'm mixing it at 1.5x what your recipe is. I'll have to mess around with it. Might not be an issue. My alk demand might have increased, I guess I'm just skeptical that it would increase much in a day or two lol

I think the effect is pretty fast, whatever it will be. It is part organism uptake and part increased abiotic precipitation. We have little data on how much of each, but the latter will be a same day effect and the former won't take long.

 

[reely989]

I think the effect is pretty fast, whatever it will be. It is part organism uptake and part increased abiotic precipitation. We have little data on how much of each, but the latter will be a same day effect and the former won't take long.

Hopefully that's the case! My luck it'll be a busted doser line or something lol

 

[Miami Reef]

I use a BRS 1.1 mL dosing pump. It adds it in drips, spread throughout the day.

I wouldn’t have it any other way.

 

[reely989]

I use a BRS 1.1 mL dosing pump. It adds it in drips, spread throughout the day.

I wouldn’t have it any other way.

Yeah I'm using a reefdose and the most it will let me do is 24 doses throughout the day. So that's about 3.5ml per dose or so. Should be pretty manageable I think.