Limewater overdose

[Cory]

In my 30 gallons i had the entire 5 gallons of 2tsp per gallon limewater go in the tank! As expected the water is cloudy. All the fish seem fine from what i can see.

Whats going to need correcting when i do the tests? Magnesium?

The overflow plugged and that caused the water to overflow the top of the tank.

 

[Flippers4pups]

Your main concern now is your salinity. If it's low, raise it slowly over the next 24 hours to get back to 1.026/35ppm. A drop in salinity is less stressful than raising salinity quickly. Alkalinity and calcium may be out of wack. That's okay for now, it will stabilize over time. Precipitation of calcium is expected and will pull the alkalinity down with it.

 

[jason2459]

Where's your pH at? Soda water will help there if need be.

 

[Cory]

Thanks guys. Yeah ill correct salinity.

I dont measure the ph or have a test for that. Got tests for everything else though.

 

[Randy Holmes-Farley Verified Community Expert]

This is a bad overdose. pH is a big concern, but you cannot correct it without a kit.

Once the water clears, you can measure alk and calcium (not before). Magnesium should be mostly unchanged once the pH is corrected.

 

[Cory]

This is a bad overdose. pH is a big concern, but you cannot correct it without a kit.

Once the water clears, you can measure alk and calcium (not before). Magnesium should be mostly unchanged once the pH is corrected.

Thanks Randy. Id imagine it happened over 5 hours or so. Nothing bad has happened to anything just a thick precipitate coated everything. Ill be testing those later. Good to know mag should be unchanged. I just assumed since its mag hydroxide it would precipitate too.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks Randy. Id imagine it happened over 5 hours or so. Nothing bad has happened to anything just a thick precipitate coated everything. Ill be testing those later. Good to know mag should be unchanged. I just assumed since its mag hydroxide it would precipitate too.

Lots of magnesium hydroxide will have originally precipitated, but it will redissolve when the pH returns to normal. The preciptiated calcium carbonate (which may have some magnesium in it) won't.

 

[Cory]

Lots of magnesium hydroxide will have originally precipitated, but it will redissolve when the pH returns to normal. The preciptiated calcium carbonate (which may have some magnesium in it) won't.

Good to know thanks. Interesting how it redissolves when the ph drops.

 

[jason2459]

Lots of magnesium hydroxide will have originally precipitated, but it will redissolve when the pH returns to normal. The preciptiated calcium carbonate (which may have some magnesium in it) won't.

Unless he would like to spike his pH the other way now. [emoji1]

 

[Myka]

Is it just fish in this tank or corals too? Now it's been a few days, is all the livestock ok? Were there any signs of stress?

Just for anyone else reading this, I strongly suggest if you're going to dose limewater that you have a digital pH meter on hand both for situations like these, and also to make sure you're not raising the pH too high regularly (using too much).

 

[Randy Holmes-Farley Verified Community Expert]

Good to know thanks. Interesting how it redissolves when the ph drops.

Magnesium hydroxide is Mg(OH)2

The solubility limit is determined by the multiplication product of the magnesium concentration times the hydroxide concentration times the hydroxide concentration again:

Ksp = [Mg] x [OH-] x [OH-]

Each drop of 1 unit in pH drops [OH-} by a factor of 10, so a drop of 1 pH units increases the solubility limit by a factor of 100.

Thus if the pH drops from 10 to 8, the solubility goes up by 100 x 100 or 10,000.

That's why the cloud of magnesium hydroxide can form locally when limewater is added, but redissolves as it mixes in.