Supicious Black Precipitate

[liveforphysics]

Tank specs in question:
30gal display with 220watts of 50/50 compacts
20gal fuge (loaded with cheato)
plenum under DSB's in fuge and display
0-ppm NO3
.1-ppm PO4
bi-weekly suplimented with "coral vite"
Tank gets cheato harvest for nutrient export
2 clowns, small CBB for bio load
Assorded soft corals

I havent skimmed the tank for about 4 months, and NO3 has always stayed zero, PO4 has always stayed at the bottom of the test.

I recently aquired the CBB to remove the aptasia that I had. It quickly removed all of the aptasia's. I had previously only fed formula 1 flake, and the fuge provided TONS of macroplankton for the rest of the tank.
After the CBB finished all the aptasias, he seemed uninterested in the flakes, so I gave the tank brine shrimp for the first time. Things were all normal until last friday, the pulseing Xenia appeared as it does in the morning when the lights just turn on. I spent the weekend in Puyallup, and when i returned sunday night, the Xenia was totally nuked. It WAS growing very fast, and spreading all over, now its a few grey smears on rocks. The toadstools and leathers also had retracted polyps.

I tested water quality, and everything is still zero'd out.
So, I fire up the skimmer for the first time in 4 months, and much to my suprize, it coughs up about 3 cups of this black grit in clear skimmate with no odor. This tank has never seen carbon, so its not chunks of carbon.

It feels dense like sand, only much finer. After the 3 cups that immeadiately jumped out, the skimmer is back to just a very slow feed rate of normal type skimmate.

Currently, the other corals appear healthy again.

So, naturally im very curious as to what the black precipitate in the skimmate was, and Im also curious as to what caused the Xenia to just vanish like free cotton candy at a fat-camp .

Any help appreciated, thanks
-Luke

 

[wrightme43]

was the skimmer left off with water in it? I know probley not but just had to ask, first thing that popped to mind.

 

[liveforphysics]

No, the skimmer was taken down, cleaned and stored in a clean place. I re-installed it just today to see if it would help.

Thank you for your response though
-Luke

 

[wrightme43]

Wow, man I sure dont know then. I cant think what the heck would make it do that.

 

[charlesr1958]

Have seen that on occassion myself, although not related to a soft coral melt down (which may have been temperature driven?) While not knowing the exact cause (big help, hey) I had always assumed it was just a binding event between an organic and a metal element. Big question is also did one of the elements come from the soft coral, or is the precipitation a sympton of what caused the softie melt down. hmmmm.

 

[liveforphysics]

Charlesr1958, I agree with you about it appearing as a metal bonded with an organic. After pouring the material into a white bowl to take a good look, that was my first thought. Maybe calcium-sulfate precipitate? I'm glad to hear that I'm not the only person who has seen this material in the skimmate.

I dont have any data logging on my temp, and I was gone for the weekend, but it has never deviated more than 2 degrees from 82 for the last many months that i have been observeing it. I will keep temp as a posibility, but I am leaning towards something else.

I just checked on the skimmer again, which has barely produced 5ml in the last 2hrs, and none of the black precipitate was present. It was really alarming how fast the skimmer removed it, appearently it has some intimate feelings for foam.


So far, im testing po4, no3, no2, nh3-4, pH, Ca, g/ml, and everything appears to be just as it was when the corals were all healthy and spreading like weeds.

Is there a test I should be doing that I have missed? Possibily some type of metal contamination?

Any help is appreciated, and thanks in advance.

 

[charlesr1958]

I think I have seen the black particle happen maybe two times over the years, most recently last year, mid summer. Would not have a clue as to its make up, but the grain size and "feel" sure felt gritty and was also suprised a skimmer could pick it up in its foam. Would think it was too heavy. Unless it was formed in the skim cup afterwards?, am at a loss myself as to what it is exactly, you are the first I have heard mention it. Having seen how widly various salt mixes can be in their composition, I think it would be wise of any hobbyist to get how ever many tests are available, not so much for knowing what to add, but knowing if a certain element has gone above NSW levels. Am and always have been totaly against any supplementation other than calcium/ph related. I should shut up now, this is beyond me. Hopefully someone else has the answer and turns out to be a common occurance with reasons known. Just find it curious that this event happened at the same time as a softie problem, may not even be related though. Hate not knowing...lol

 

[liveforphysics]

Well, after haveing the skimmer run for a few days, I have about 5 to 10 times the phosphate I had before turning on the skimmer, and my cheato growth has dropped back a little. The tank does look very well again though.

I pulled the skimmer out, and I will be adding some nitrate directly to the fuge to try to feed the cheato growth for sucking down the phosphates.

So, by chance does anybody have a little chunk of Xenia looking to see the world? Or at least northseattle?

 

[Ed Hahn]

Liveforphysics,
I have heard repeatedly and believe the smaller the tank the more changes due to sensitivity of evaporation. The first thing I would check as Charles recommended would be temperature. Xenia melt quite easily I think around 84 degrees. Your tank temperature swings easily to room temperature unless you have a controller with precise temperature control and heaters and chillers working accordingly. Temperature swings would produce skimmate. Anything left un eaten and dead produces waste or phosphates. Your chaeto might react also to high temperature(?). Your tank being smaller will swing very easily. Temperature changes, animals stress, animals release amonia, changes PH, anytime salinity swings the other parameters are affected. Constant changes due to light, temperature, stress of animals, feeding, flow to anerobic bacteria, It sounds complicated, but they all work together.
It would be a awesome idea for you to see Meeting at Shark Reef on the 21st. I am sure Mark will be discussing this. Your local reef club, and RF is a support system for issues like this. Someone from a meeting visiting your tank might recognize something small you may not, Say a tank completely covered not allowing gas exchange, etc. The 21st would be a good time to ask one on one while stuffing your face with Pizza.
wishing you find the issue and it is solved quickly,
sincerely,
Ed

 

[Boomer]

There is no way of telling what it really is without testing it. There are many typies of black precip's to include Ion sulifides, i.e., FeS and FeS2. Many, as you guys suggest, are metals sometimes tied to organics.

Calcium sulfate would not be one of them, as it is usaully white. It is the mineral Anhydrite and you just will not see it form in a skimmer. All most all of it is formed by the dewatering of Gypsum. Such minerals only form under extreme evaporation. It only leaves solution when there is only about 9.5 % of the orginal water volume left. That means, if you had a litter of seawater, you would have to evaporate 90.5 % of the water before it starts to form a precip.

 

[liveforphysics]

Thank you very much for your input Ed and Boomer.

So, far, my friend who runs Below Sea Level told me the problem was a lack of Iodine, I belive this could be possible. Ed tells me it could be temperature, which certianly seems possible, as i do run the temp hot, and I havent built a microcontroler setup to auto control my DIY chiller. None of these explain the wacky precipitae though (which might not be related at all).

After adding a little nitrate, the softys all seem to look the best they have in months. I am confident the nitrate will all be stored in the tissue of cheato in 1-2 days, I am excited to see if it takes the P with it.

Another possibiliy with reguards to the precipitate could be from the 2 month period with no waterchanges, and a fair share of tap water top-offs...


Ed, thank you for inviteing me to the meeting on the 21st. I am looking forward to meeting you guys, Im sure it will be a great time.

-Luke

 

[ethanriley]

I have had this precipitate before when I had a temperature swing in my thirty gallon from my halimeda. I deduced it came from the halimeda because the particles were all attached to it. My belief though didn't test it was that it was an iron oxide. Do you supplement iron for the chateo? I have also seen it in areas where halimeda and cualerpa grow heavily. Just my two cents definitely a metal oxide I think.

 

[liveforphysics]

There is iron in the suppliment solution that I occasionally add, along with many other metals. I am pretty sure that its some type of metal. Since adding a bit of Iodine, the whole xenia problem is fixed and things are back to soaring growth again. I nearly broke down and water changed in my panic... silly iodine deficiency had me all in fluster...

Thank you for the tip that it may be an iron compound. If I ever get some quanity of it again, I will perform qualitative analisis on the compound and figure it out for sure. Unfortunately, I dont forsee myself sticking the skimmer on the tank anytime, but if I ever do, I will be sure to collect the precipitate and test it.