Precipitation- How can I reverse?

MichaelReefer

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Everything was going fine and all of a sudden I started to get some precipitation in my tank- Sand is turning hard, alk and calcium dove fast and now I cant get it back up no matter how much I dose. I dose 2 part, Seachem Fusion 1 & 2. have never had this problem.

How do I get my tank back to normal? I cant get the levels back up and keep them up.

@Randy Holmes-Farley
 
If it were me, I'd so something in approximately this order....
Stop Ca/Alk additions.
Stop any CO2 scrubbing or other pH elevating measures etc.
Then check my salinity a couple of different ways and lower it if needed to 1.026 SG
Then I'd check my Mg and elevate it to the target range (1300-1350).
give it a day or two, to make sure that has stopped the precipitation, then I would move Ca and Alk to a reasonable target.
 
Totally agree with taricha approach, additionally it would help if you publish your tank parameters and chemistry, dosing amount.


Currently ALK dove to 6.85 (Normally 8.0)
Calcium 350 (Normally 450-480)
MG 1418
PH 8.23
Salinity 1.026

Was dosing 100mg of DKH and 100mg of Calcium.

How exactly would I know it "stopped?"
 
You cannot reverse it, but you can slow or prevent future precipitation:

Once a calcium carbonate precipitation event is initiated (due to high alk and pH, for example), you need to break the cycle because the surfaces of any precipitate act as good seed crystals for more precipitation until soemthing gets onto those surfaces and blocks further precipitation.

Here's my generic advice for such scenarios:

1. Stop all efforts to boost pH.
2. Stop dosing alk for a bit and let it decline.
3. Reduce pH by switching to a low pH alk mix like sodium bicarbonate, or a calcium organic such as Tropic Marin All for Reef.
4. Ensure magnesium is normal to high.
5. Keep organics and phosphate on the high side.

After a few days of not dosing alk, restart slowly, adding additives to a very high flow area so it mixes in fast.
 
You cannot reverse it, but you can slow or prevent future precipitation:

Once a calcium carbonate precipitation event is initiated (due to high alk and pH, for example), you need to break the cycle because the surfaces of any precipitate act as good seed crystals for more precipitation until soemthing gets onto those surfaces and blocks further precipitation.

Here's my generic advice for such scenarios:

1. Stop all efforts to boost pH.
2. Stop dosing alk for a bit and let it decline.
3. Reduce pH by switching to a low pH alk mix like sodium bicarbonate, or a calcium organic such as Tropic Marin All for Reef.
4. Ensure magnesium is normal to high.
5. Keep organics and phosphate on the high side.

After a few days of not dosing alk, restart slowly, adding additives to a very high flow area so it mixes in fast.


What generally "starts it"? My PH and Alk have been stable at that level for a year and it randomly happened?
 
What generally "starts it"? My PH and Alk have been stable at that level for a year and it randomly happened?

New sand is very susceptible, and high alk and pH are the biggest drivers. Very low magnesium, phosphate and organics also contribute, as would mostly new salt water.

Over time, sand gets coated with phosphate, magnesium and organics that prevent precipitation.
 
New sand is very susceptible, and high alk and pH are the biggest drivers. Very low magnesium, phosphate and organics also contribute, as would mostly new salt water.

Over time, sand gets coated with phosphate, magnesium and organics that prevent precipitation.

Well, that does make sense I guess- I moved my tank and went back to a sandbed about three months ago.
 
Everything was going fine and all of a sudden I started to get some precipitation in my tank- Sand is turning hard, alk and calcium dove fast and now I cant get it back up no matter how much I dose. I dose 2 part, Seachem Fusion 1 & 2. have never had this problem.

How do I get my tank back to normal? I cant get the levels back up and keep them up.

@Randy Holmes-Farley
Curious, can u pls share what are some other the signs of precipitation besides sand turning hard?
 
Curious, can u pls share what are some other the signs of precipitation besides sand turning hard?

Excessive buildup of calcium carbonate on heaters and pump impellers, since warm objects precipitate more.
 
What is that Precipitate in My Reef Aquarium? by Randy Holmes-Farley - Reefkeeping.com

Figure 2. Calcium carbonate can form thick deposits on heaters.
It is the heat itself that helps drive this precipitation.

1674152977452.png
 
@Randy Holmes-Farley , should I be worried about my Alk dropping too low in the time I am not dosing? Should I add some baking soda to keep it up above 7 or will that do the same thing as adding 2 part and cause more?

If it stays above 6 dKH, I would not worry.
 
If the goal is to prevent calcium carbonate precipitation, while still adding some alkalintiy, then either sodium bicarbonate (as in baking soda or low pH two parts) or an organic form such as All For Reef are the best choices.
 
If the goal is to prevent calcium carbonate precipitation, while still adding some alkalintiy, then either sodium bicarbonate (as in baking soda or low pH two parts) or an organic form such as All For Reef are the best choices.

Oh, I thought Soda Ash reduces the chance of getting Precipitation? Not a science-y person haha.
 
Last edited:
Oh, I thought Soda Ash reduces the chance of getting Precipitation? Not a science-y person haha.

Nope. It's a middle tendency as it raises pH. Bicarbonate lowers pH a tad, and the other alternative, hydroxide, raises pH a lot.
 

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