Repeatedly getting precipitation- cant figure it out

MichaelReefer · Aug 21, 2023

Well I have posted about this before but cant seem to get an actual answer... The last year or so I have had about 4-5 episodes of precipitation... I get everything balanced and stable and out of no where my Alk crashes, sand turns to rock.... I stop dosing Soda Ash for a few days and restart, slowly dosing to bring it back up. Then it stays stable for a month or two...then repeat. And so on and so on.

It just happened a few weeks ago...the wife and I went on a vacation and just like always I poke in on my Apex and notice my numbers are dropping...by the time I get back my alk was at 6.10. Not really sure what could be causing it or why. I have dosed for years and never had this problem, especially when the tank is stable for months and it happens out of no where. Appreciate any help.

@Randy Holmes-Farley

BranchingHammer · Aug 21, 2023

MichaelReefer said:
Well I have posted about this before but cant seem to get an actual answer... The last year or so I have had about 4-5 episodes of precipitation... I get everything balanced and stable and out of no where my Alk crashes, sand turns to rock.... I stop dosing Soda Ash for a few days and restart, slowly dosing to bring it back up. Then it stays stable for a month or two...then repeat. And so on and so on.

It just happened a few weeks ago...the wife and I went on a vacation and just like always I poke in on my Apex and notice my numbers are dropping...by the time I get back my alk was at 6.10. Not really sure what cold be causing it or why. I have dosed for years and never had this problem, especially when the tank is stable for months and it happens out of no where. Appreciate any help.

@Randy Holmes-Farley

Do you test for magnesium? Oftentimes, this is caused by low magnesium levels. Also, how high are you maintaining your alk?

MichaelReefer · Aug 21, 2023

BranchingHammer said:
Do you test for magnesium? Oftentimes, this is caused by low magnesium levels. Also, how high are you maintaining your alk?

I do. I keep my Magnesium approx 1350.

I generally try to keep my alk around 8.50.

MichaelReefer · Aug 21, 2023

MnFish1 · Aug 21, 2023

I might question your measurements - or - when you left town - did you have less windows open than normal etc.

Court_Appointed_Hypeman · Aug 21, 2023

Do you monitor your PH? I had a small amount of percipitation when my PH started peaking at 8.48 right on the glass at the dosing site, this cascaded into a lot of percipitate at that site climbing out of the water, slowly reducing my alk, I solved this by scraping away the peripitate and moving my dosing tubes from touching the glass by using a magnetic holder, I was using a bucket clip prior.

But my percipitate was very local, though it did consume more and more of my alk.

Randy Holmes-Farley · Aug 22, 2023

Calcium carbonate is supersaturated in all reef tanks unless the pH is very low (below 7.8).

Thus, calcium carbonate "wants" to precipitate, but is slowed by the lack of seed crystals to allow ready ongoing precipitation.

Normal bits of solid calcium carbonate get clogged on their surface with phosphate, magnesium, organics, and organisms such as bacteria

If something happens to tip the balance and precipitation starts, it can run away and keep going until you deplete it (which, with dosing, may never happen).

The biggest driver of precipitation is having carbonate unusually high. That can happen with a simple rise in pH, as might happen when you are away (less CO2 in the home air). A rise of 0.3 pH units is the same as a doubling of alkalinity in terms of precipitation potential.

High alk, of course, is also a bug driver.

High calcium is less of a driver. No one has a doubling of calcium to 840 ppm without an overdose scenario, but alk sometimes doubles and pH often drives carbonate very high.

This is my generic recommendation for precipitation issues (e.g., hardening sand, seizing pumps, etc.):

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.

MichaelReefer · Aug 22, 2023

Randy Holmes-Farley said:
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.

Yeah, I do this every time it happens, get it back to normal and it randomly happens again.

I think it was more of a coincidence it happened when we went out of town because it has happened when we are home too.

My PH normally runs from 7.8 at night to 8.0 during the day.

MichaelReefer · Aug 29, 2023

Just happened again...

Court_Appointed_Hypeman · Aug 29, 2023

If I were in your shoes, I would get a secondary method of monitoring PH just to see if it spikes.

My PH with a packed house sealed tight that used to sit at 7.8 to 7.9 at 12dkh. After getting new lights, it started climbing quick in PH and that's when my percipitation first started, but luckily it was very isolated, but my DKH fell to 8, while my PH now 8.45, I am scared to run my alk any higher so I just keep it to where it fell.

I'm not sure PH is your issue, but I would start with varifying its not getting super high and your current method of measuring isn't failing you. If you hit that tipping point of high PH causing the supersaturated state of alk and calc to no longer stay saturated, it would do exactly what you describe.

I am not as experienced as you, just giving you ideas. I would almost put money on it being PH though as mine gets really high if we are gone for a day, and the timing of your previous event.

MichaelReefer · Aug 30, 2023

My PH is pretty consistent. I had that small drop from the 26th to now due to stopping my Soda Ash dosing to get the Precipitation under control.

Court_Appointed_Hypeman · Aug 30, 2023

Definitely not dangerous levels of PH to cause percipitation. I would check calibration or attempt to verify it further.

Do you run a co2 scrubber? I have an issue most likely due to carbon dosing where my skimmer, even though I run it super dry, makes bubbles that are so strong they don't pop and have on occasion almost has liquid get past all of my capture solutions on the air line to the scrubber media, which can introduce thenhydroxide and subsequently make percipitation likely.

MichaelReefer · Aug 30, 2023

Court_Appointed_Hypeman said:
Definitely not dangerous levels of PH to cause percipitation. I would check calibration or attempt to verify it further.

Do you run a co2 scrubber? I have an issue most likely due to carbon dosing where my skimmer, even though I run it super dry, makes bubbles that are so strong they don't pop and have on occasion almost has liquid get past all of my capture solutions on the air line to the scrubber media, which can introduce thenhydroxide and subsequently make percipitation likely.

I used to run a scrubber but dont anymore.

MichaelReefer · Sep 1, 2023

@Randy Holmes-Farley Should I go to Bicarb? Will that decrease my chance of Precipitation?

RichReef · Sep 1, 2023

Soda ash has clumped my sand every time I've attempted to use it. Never figured it out just stopped using it. Multiple MG tests and endless testing. A few ICP tests also.

MichaelReefer · Sep 1, 2023

RichReef said:
Soda ash has clumped my sand every time I've attempted to use it. Never figured it out just stopped using it. Multiple MG tests and endless testing. A few ICP tests also.

Its just getting really frustrating. This is happening about every month now. I get it where I want it for WEEKS, then all of a sudden have a massive drop into the 5s or low 6s....I stop dosing for 2-3 days. Then have to start all over again to get it back up.

The BRS calculator says I should only does about 22ml a day...but 22 wont keep my DKH up... @Randy Holmes-Farley

RichReef · Sep 1, 2023

MichaelReefer said:
Its just getting really frustrating. This is happening about every month now. I get it where I want it for WEEKS, then all of a sudden have a massive drop into the 5s or low 6s....I stop dosing for 2-3 days. Then have to start all over again to get it back up.

The BRS calculator says I should only does about 22ml a day...but 22 wont keep my DKH up... @Randy Holmes-Farley

It was happening a few years ago. The 2 ICP samples I sent out were taken during the problem. I was dead set on moving to the BRS 2 part because it was going to save me a fair amount of money. I never figured it out. At that time my PH was in 7.9 to 8.1 range. I even bought a magnetic stirrer to fully dissolve it. Even adding fully dissolved it still precipitated as soon as I added it to my tank water. I stopped using it and went back to my go to. I pulled the sand clumps and added some new sand slowly to replace it. When I broke that tank down sand was cemented to the rock work.

I'm not sure you will find the problem. You and I are not the only ones to have this problem with soda ash. I have a friend who uses it with no issues at all. Go figure.

3 weeks ago I moved to kalk because my 2 part was getting too expensive.

Randy Holmes-Farley · Sep 1, 2023

MichaelReefer said:
@Randy Holmes-Farley Should I go to Bicarb? Will that decrease my chance of Precipitation?

Yes. It will lower pH and the chance for precipitation.

When you say it happened again, what exactly happened?

Randy Holmes-Farley · Sep 1, 2023

MichaelReefer said:
Its just getting really frustrating. This is happening about every month now. I get it where I want it for WEEKS, then all of a sudden have a massive drop into the 5s or low 6s....I stop dosing for 2-3 days. Then have to start all over again to get it back up.

The BRS calculator says I should only does about 22ml a day...but 22 wont keep my DKH up... @Randy Holmes-Farley

The calculator tells you an amount that is independent of alk need? What is it using to calculate an amount?