left my Kalk reactor on all night

[karimwassef]

I was experimenting last night and had the kalk reactor dosing on manual on.

I got sleepy and left it on all night draining my entire 100gal RODI reservoir through it.

My pH climbed from 8.34 to 8.8 ... only slowing down as the reservoir ran out of water...

The alarm was blasting but I had the phone off and I can't hear the audible alarm upstairs...

Since it was on manual, it couldn't stop itself.

I didn't even have any water for a water change!

So far - this sounds like a total and complete wipeout...

But - here's what happened:

I turned off the Kalk reactor (obviously).

The Alk went up from 7.5 to 9. I turned all lights off all day to avoid Alk burns.

I don't understand how my Alk didn't EXPLODE... My air injector uses fresh air which was ~ 380ppm CO2.

A couple of other details. My Salinity dropped from 36ppm to 31ppm.

My Mg is usually at 1600 and was 1300 in the morning.

My Ca is usually at 500 and was 480 in the morning. No chalk storm.

Over the next 8 hours in the dark, my pH dropped down to 8.2. I restarted my doser and it's back at 8.34 and steady. Alk at 8.

I finally made 100 gallons of water and made 100gal water change...

No corals are dead or even looking bad.

So ... what happened?

Did the Mg precipitate with the excess carbonate?

[karimwassef]

By the way, I did have a Kalk disaster that did severely kill my corals in the past. In that case, the CO2 was very high (800-1000ppm) which dropped my pH significantly... this drove excessive dosing WITHOUT a significant pH increase.

The biggest difference I see between that deadly scenario and this one is the CO2 ppm entering the system.

[orcafood]

That air injection system must have helped out a bunch. Kalk ODs kind of work themselves out usually because the high pH precipitates carbonates. As you saw magnesium coprecipitates as if it were its job. Likely all the carbonate created had its high surface area quickly poisoned by incorperated magnesium. 8.8 is way up there you musta had a snow storm! I bet you were pretty close to an od situation like last time. Did you have the air injection system in the previous system fail?

[Piper27]

I would guess a big drop in salinity would hurt more than a small rise in alk. Especially if it wasn't corrected right. Your lucky your system is so used to a large amount of kalk going in! Would like to hear updates in a week or two to see how your birdsnest fair. How quickly did you bring the salinity back up?

[orcafood]

the sailinty is controlled by many ions, i wonder what exactly precipitated to drop the salinity like that. Water changes will be necessary to restore to seawater balance. Who is to say that the balance you have now isn’t going to work though.

[karimwassef]

The system is 600gal and went to 700gal diluted ... I used to have a massive surge so my system was designed to handle a lot of excess water... that's a big driver in my Mg drop, not just precipitation.

So, I can't speak to what was happening in the middle of the night; but in the morning, the tank was crystal clear... no snowstorm at all! I don't think it ever happened. No dust on anything.

Yes, the last time a kalk overdose happened, my injector was offline for repairs... that's what killed it. The outside air is very low CO2 but steady. Drives massive stability in my gases.

[karimwassef]

Good news is that I also sold or gave awa most of my sps coral since I'm getting ready to move. So every coral has a frag out there to maintain it.

The sps now in the tank are all the bases that have since grown new heads and need refragging.

[FireReeferSteve]

How did you not have a flood with an extra 100 gallons going into your system?


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[karimwassef]

It's a big system. 600 gallons usually and design for a massive surge that's now offline. The 100 gallons just brought it close to the top.

In my morning panic, I opened the release that flushes tank water directly to the sink drain... fully expecting to add 100 gal of fresh saltwater when done... and got the water level down to the return pumps (tank return bubbling)... and then realized I HAVE NO RO WATER!! So the tank sat in the dark, bubbling away as I made a fresh batch ~ 24hrs

[karimwassef]

[bertoni]

The loss of magnesium is a little more than I'd expect from the salinity drop, but probably not completely out of line. There might be a bit of magnesium carbonate that is yet to redissolve. I'm not sure why the calcium level didn't change more.

[karimwassef]

I can't explain it.

[orcafood]

lol the corals do not seem to mind

[karimwassef]

True but it's important to understand what happened. In case these events happen in the future, it would be valuable to understand what protected my reef from an otherwise certain disaster.

[orcafood]

I would guess that it was your air injection system. The only gas contained in air with sufficient concentration that would have helped your situation would be CO2. Your system pulls equilibrium very hard, in either direction. The CO2 is used up as it is replaced. In a tank with a smaller air injection system, the CO2 would deplete and then the precipitation plus pH spike (over 8.8, you must have been close) begin.

All that calcium is somewhere in your system, no question. Such an aggressive air injection system with sufficient mixing could probably make some very very fine, high adsorption, and mobile CaCO3 (plus poisoning ions). How are the nitrate and phosphate levels today? Is the tank very clear?

[karimwassef]

Yes.. no dust or cloudiness

[bertoni]

I agree that aeration is the only mechanism that could have limited the spike in the tank.

[karimwassef]

So how did it do it?

The CO2 was constant at ~ 380ppm.. but pH was 8.8

Why didn't Alk go through the roof?

[orcafood]

The calcium as well as carbonate are surely in the tank somewhere. If it is not showing up on test kits then it is probably not dissolved into the water but it is precipitated somewhere? It is bound/ settled in some manner to a solid surface. PH meter might need a clean too after a pH that high.

My guess is the same though you must have made insoluble caco3 almost as quickly as the caoh2 was added? That would support the huge magnesium (and likely other ions/ inorganics/ organics) drop due to such a high surface area needed to be poisoned.

Arent your co2 levels measuring incoming air rather than co2 in tank water? I’d bet the co2 level in the tank did drop.

I’d wager your phosphates are pretty non existant after the kalk OD?

[karimwassef]

My P is always under measurement levels because of my extra large algae scrubber.

If it all precipitated, I would expect a dusting over the rocks and that much kalk would have turned the tank milky white.

With 1600 Mg to start with, why didn't the Alk go up to 12 or 13 before precipitating? Why just 9?

[karimwassef]

Also, the air injection would have been acting to stabilize the pH, not Alk. Given the 100 gal of kalk, my pH should have been 9-10 assuming the 600 base volume was at 8.4 and the 100gal of kalk was at 12? That's an insane influx of OH-.
The excess CO2 definitely curbed the pH spike but it would have just converted the OH- to CO3 2- in abundance... the Mg should have interfered to allow the Alk to rise to 12-13 before precipitating and then there would have been dust.

Maybe the injector's action like a skimmer frothed up the dust as fast as it was being created but no skimmer is 100% effective. And the froth head in the aux sump where I inject would have been massive... no significant froth.

[orcafood]

Just because you can't test for po4, doesn't mean the levels didn't drop though. I expected a dusting too. The fact that there is no dusting means to me that the CaCO3 is somewhere in the sump, it is not in the display? It is definitely not in your water right as you can test for alkalinity? But it was poured into the tank so it is somewhere.

Depends on how fast the magnesium dropped. If kalk is pouring in pretty steadily it could have very quickly depleted out the magnesium as hydroxide at the point where the kalk pours in. Precipitation is all about the pH of the water around the ions. A kalk stream is pretty basic so magnesium has a higher chance of interacting with a basic enough environment to precipitate. After magnesium is gone, nothing is there to keep the calcium carbonate from precipitating. All of this happened just where that steady stream, high pH environment was created in the sump.

https://en.wikipedia.org/wiki/Magnesium_hydroxide

"PREPARATION:
Combining a solution of many magnesium salts with alkaline water induces precipitation of solid Mg(OH)2:

Mg2+ + 2 OH− → Mg(OH)2
On a commercial scale, Mg(OH)2 is produced by treating seawater with lime (Ca(OH)2). 600 m3 of seawater gives about one ton of Mg(OH)2. Ca(OH)2 is far more soluble than Mg(OH)2, the latter precipitates as a solid:[5]

Mg2+ + Ca(OH)2 → Mg(OH)2 + Ca2+"

I think the froth head did exactly what you described. Since pH was stable in most of the tank nothing precipitated throughout the whole water column. But the pH must have been high enough to precipitate MgOH2/CaCO3 around where the effluent from your kalk reactor bleeds into the sump.

[karimwassef]

My effluent drip is a very slow thin stream and enters at the start of my sump where water first enters. It flows at about 5000gph to the other end of the sump where it's returned.

I know I have P... I just can't measure it before or after the event.

I am starting to notice something funny in my algae scrubber... there's a kind of scummy buildup (I'll take a picture) that looks like dirty brown foam but it much more like a gel.

But this appears 4 days after the event?

[bertoni]

I agree that there likely was some precipitation, but I have no idea what the details might have been. The Kalk might not have been very concentrated, I suppose, although we might also be looking at some sort of testing issue.

[karimwassef]

the kalk was potent enough to increase pH against the forces of the constant CO2 injection.

I use 3 cups of kalk in a 3 gallon container. It's a white mud under a clear effluent.