Brown dusty particles accumulating in sump - not diatoms

spicymikey · Mar 24, 2024

Over 6 months ago I started getting a lot of these particles on the bottom of my tank and sump. I'm not a new aquarist and even this current 400gal system is over 3 years old, but I am stumped on identifying and eliminating this rapidly accumulating brown dusty particles in the sump and tank. I vacuum the bottom of this 2nd chamber each morning and this is what it looks like the next morning. So this is 24hrs of accumulation just in the sump alone.

It does not cling to anything. Not even itself. So, its like a dust that will blow around if disturbed. Its heavy. Will settle to the bottom of a 2inch container within 10 seconds. It has no odor. It has no distinct taste (yes I tasted it LOL).

1) Diatoms? Sure, my first thought was diatoms even though it seemed way browner than you'd expect. See pics under natural light with a phone camera.

So, I scooped some out and looked at it under 1200x. The lighter brown particles are what make up most of the items so I am focusing on them. It does not appear to have any structure . Looks like irregular shaped round shaped. At 1200x my eyes see no geometric shapes or repeating patterns. A few of the things in this still shot were moving but these light brown things had no motion.

2) Precipitate? Maybe but its brown. Can't be calcium based. Maybe its an iron molecule. Iron Oxide, Iron Hydroxide? I did try the magnet test and it showed no signs of being magnetic. I read that Iron Hydroxide will not show any signs of being magnetic like Iron Oxide (rust) would be.

3) Iron Hydroxide? I dose with Sodium Hydroxide to control PH and create carbonates. I also drip dose a chelated Iron from Brightwell Aquatics to maintain an iron level at around 0.01-0.02ppm (based on a Hanna tester). So maybe thats it! So I stoped dosing Iron for 4 days and waited. Iron level is now undetectable withe the Hanna but as of this morning, still tons of this stuff.

4) Unknown organic organism? I tried putting some in a 12% solution of Hydrogen Peroxide. Thats fairly strong. Will start irritating your skin within 10 seconds. I let this stuff sit in it for 30 minutes. It did not break down. No fizzing. No reaction at all. So I find it hard to believe its some algae, etc.

So I'm stumped. Any suggestions?

Thanks in advance. Mike

BOYERZ · Mar 24, 2024

Detritus

Lavey29 · Mar 24, 2024

Lbrdsoxfan · Mar 24, 2024

BOYERZ said:
Detritus

Yup it's mulm (decomposing organics). You can leave it or get rid of it.

I don't worry about it.

taricha · Mar 24, 2024

suck up a little and put in a test tube. Add a little hydrochloric acid - if it's like the stuff from my tank, the majority cleared and what was left behind was brown organic detritus that's the end result from breakdown of food and waste. It's got pretty low nutrient value and probably doesn't do much.

spicymikey · Mar 25, 2024

BOYERZ said:
Detritus

Well detritus is just a general term. Any suggestion as to what exactly it is? Remember it's pretty much all one thing. Also, it accumulates rapidly overnight. We know one thing, this "detritus", whatever it is, is not organic and is mostly mineral deposits of some kind. Thanks

spicymikey · Mar 25, 2024

Thanks for all the comments on it just being detritus, mulm and general decaying organics. That's certainly the obvious thought but the problem is it's accumulating way too fast. There's only about 10 fish of moderate size in this 400 gallon system and the amount of particles on the bottom are more than the amount of food being fed. Also, when I try and break it down with high concentration hydrogen peroxide there is no reaction. So whatever it is it's not organic. If we look at the 1200X view of this stuff we can see it's mostly tiny particles of something that are light brown. Sure there are a few other items in there that are other things including some living organisms moving around that you can't see in a still shot, but 95% of it is the same particle. So I'm assuming it's some kind of precipitate but can't be certain exactly what it is. Was hoping somebody may have run into this before.

spicymikey · Mar 25, 2024

taricha said:
suck up a little and put in a test tube. Add a little hydrochloric acid - if it's like the stuff from my tank, the majority cleared and what was left behind was brown organic detritus that's the end result from breakdown of food and waste. It's got pretty low nutrient value and probably doesn't do much.

I have not tried putting it in an acid solution I could always try that to see what happens. But remember I put it into a 12% hydrogen peroxide and I saw no reaction so I'm thinking it's not organic

spicymikey · Mar 25, 2024

Lbrdsoxfan said:
Yup it's mulm (decomposing organics). You can leave it or get rid of it.

I don't worry about it.

I'm thinking that's part of it but there's something else going on here. Another clue is that this rate of accumulation has not always been this fast. I can clog up a 12x20-in filter pad in 24 hours. So it's something more than that. Also, this tank is 3 years old and the amount of fish and the type of feeding has really not changed yet the rate of accumulation of this stuff has increased five fold recently

spicymikey · Apr 4, 2024

Wanted to circle back on this thread I started. After some more research and experimenting, I've come to the reasonable conclusion that this extra "detritus" in the sump is related to a change I made a couple months ago with one of my dosing concoctions. I have a 10L container that supplies my calcium needs from an auto doser. It is a saturated solution of BRS Calcium Chloride and 1000ml of Tropic Marin K+. This has worked well over time but I was finding my Fe needs were exceeding what was provided with this. I decided to supplement it with some Brightwell Ferrion. That was the mistake. BW Ferrion is sodium Ferric EDTA. A chelated form of iron to works well when dosed directly to the tank. It also plays nice with Brightwell's Iodide supplements and can be combined in a dosing container. BUT, this does not work with a saturated solution of Calcium Chloride. Evidently the EDTA disassociates with the Sodium Ferric and interacts with the Calcium Chloride to create an insoluble solid of Calcium and Iron. When I changed up that mix and separated the BW Ferrion into a separate dosing container, the excessive brown particles went away.

Here is a Anthropic explanation of what happened. Makes sense, but of course, anyone who has used these generative AI engines knows they can get things wrong and hallucinate some times. So, take it with a grain of salt but it seems to make sense. Hope this is useful to others and will reminds us all to be careful playing mad scientist without being sure of the interactions.

Anthropic response to the question of the reaction:

Here's the sequence of events that occurs when sodium ferric EDTA solution is mixed with a saturated calcium chloride solution, leading to the formation of the persistent, insoluble brownish precipitate:

Initially, there are two separate solutions - sodium ferric EDTA (Na+Fe(EDTA)-) and calcium chloride (CaCl2).
Upon mixing the solutions, the EDTA chelating agent from the sodium ferric EDTA immediately begins to react with the calcium ions (Ca2+) present in the calcium chloride solution.
The EDTA chelates the calcium, forming an insoluble calcium EDTA complex (Ca(EDTA)-) that starts to precipitate out as a whitish solid: Na+Fe(EDTA)- + Ca2+ → Ca(EDTA)- + Na+ + Fe3+
Simultaneously, the ferric ions (Fe3+) released from the sodium ferric EDTA undergo hydrolysis reactions, forming insoluble iron oxide/oxyhydroxide species like Fe(OH)3.
The negatively charged calcium EDTA precipitate particles and the positively charged iron oxide/oxyhydroxide species are electrostatically attracted to each other.
The iron oxide/oxyhydroxide species co-precipitate with or adsorb onto the surface of the calcium EDTA particles, coating them with a brownish layer of iron species.
This results in the formation of stable, insoluble, finely divided composite particles consisting of a calcium EDTA core coated with iron oxide/oxyhydroxide species.
These brownish composite particles, being insoluble and oppositely charged, aggregate together and settle at the bottom of the tank, forming a persistent precipitate layer that resists breaking down or re-dissolving.

This persistent, insoluble precipitate remains stable and settled unless conditions are significantly altered (e.g., extreme pH changes, addition of strong complexing agents) that could potentially break down or re-dissolve the components.

Freenow54 · Apr 4, 2024

spicymikey said:
Over 6 months ago I started getting a lot of these particles on the bottom of my tank and sump. I'm not a new aquarist and even this current 400gal system is over 3 years old, but I am stumped on identifying and eliminating this rapidly accumulating brown dusty particles in the sump and tank. I vacuum the bottom of this 2nd chamber each morning and this is what it looks like the next morning. So this is 24hrs of accumulation just in the sump alone.

It does not cling to anything. Not even itself. So, its like a dust that will blow around if disturbed. Its heavy. Will settle to the bottom of a 2inch container within 10 seconds. It has no odor. It has no distinct taste (yes I tasted it LOL).

1) Diatoms? Sure, my first thought was diatoms even though it seemed way browner than you'd expect. See pics under natural light with a phone camera.

So, I scooped some out and looked at it under 1200x. The lighter brown particles are what make up most of the items so I am focusing on them. It does not appear to have any structure . Looks like irregular shaped round shaped. At 1200x my eyes see no geometric shapes or repeating patterns. A few of the things in this still shot were moving but these light brown things had no motion.

2) Precipitate? Maybe but its brown. Can't be calcium based. Maybe its an iron molecule. Iron Oxide, Iron Hydroxide? I did try the magnet test and it showed no signs of being magnetic. I read that Iron Hydroxide will not show any signs of being magnetic like Iron Oxide (rust) would be.

3) Iron Hydroxide? I dose with Sodium Hydroxide to control PH and create carbonates. I also drip dose a chelated Iron from Brightwell Aquatics to maintain an iron level at around 0.01-0.02ppm (based on a Hanna tester). So maybe thats it! So I stoped dosing Iron for 4 days and waited. Iron level is now undetectable withe the Hanna but as of this morning, still tons of this stuff.

4) Unknown organic organism? I tried putting some in a 12% solution of Hydrogen Peroxide. Thats fairly strong. Will start irritating your skin within 10 seconds. I let this stuff sit in it for 30 minutes. It did not break down. No fizzing. No reaction at all. So I find it hard to believe its some algae, etc.

So I'm stumped. Any suggestions?

Thanks in advance. Mike

Why not just vacuum it out. I had issue until I started using a good filter now it all collects in it and I throw it out at water change time. I assumed it was old food. However previous comment may be true I am no expert. The filter material I use is fabric that is meant to stuff pillows ect it comes from a fabric store is cheap and different densities. They carry it on a big roll

Freenow54 · Apr 4, 2024

Sorry did not see your ie read your entire post about vacuuming

spicymikey · Apr 4, 2024

Freenow54 said:
Why not just vacuum it out. I had issue until I started using a good filter now it all collects in it and I throw it out at water change time. I assumed it was old food. However previous comment may be true I am no expert. The filter material I use is fabric that is meant to stuff pillows ect it comes from a fabric store is cheap and different densities. They carry it on a big roll

Yep that's what I was doing but it's a lot and I was vacuuming everyday and going through a filter pad everyday as well. So I was trying to find the source of the problem to correct it

Freenow54 · Apr 4, 2024

spicymikey said:
Yep that's what I was doing but it's a lot and I was vacuuming everyday and going through a filter pad everyday as well. So I was trying to find the source of the problem to correct it

I would like to know as well. We shall see

taricha · Apr 5, 2024

spicymikey said:
The EDTA chelates the calcium, forming an insoluble calcium EDTA complex (Ca(EDTA)-)

That sentence doesn't make sense to me. Chelating agents increase the solubility in my experience.

But I agree that Fe is hard to keep in solution and mixing it with a concentrated additive may make it precipitate much faster. How much Fe are you adding to accumulate that much presumably Fe-related solids?

spicymikey · Apr 6, 2024

taricha said:
That sentence doesn't make sense to me. Chelating agents increase the solubility in my experience.

But I agree that Fe is hard to keep in solution and mixing it with a concentrated additive may make it precipitate much faster. How much Fe are you adding to accumulate that much presumably Fe-related solids?

500 mL of this Brightwell product in 10,000 ml container of this calcium chloride solution. Any other thoughts on what this brown particle was?

taricha · Apr 8, 2024

spicymikey said:
500 mL of this Brightwell product in 10,000 ml container of this calcium chloride solution. Any other thoughts on what this brown particle was?

I had one more thought actually.
If you suck up a couple of mL of water with some of this brown material in it, and add a few drops of bleach, I expect that organics would be bleached in a few minutes, but Fe particles would stay brown.

You might also be able to dissolve the brown particles in vinegar if they were Fe-based and brown organics would do nothing, (but I'm less confident that all likely forms of Fe would dissolve that way).

spicymikey · Apr 8, 2024

taricha said:
I had one more thought actually.
If you suck up a couple of mL of water with some of this brown material in it, and add a few drops of bleach, I expect that organics would be bleached in a few minutes, but Fe particles would stay brown.

You might also be able to dissolve the brown particles in vinegar if they were Fe-based and brown organics would do nothing, (but I'm less confident that all likely forms of Fe would dissolve that way).

Yes I tried something like that. I took a bunch of it out of the water after looking at it under a microscope and put it into a solution of 12% hydrogen peroxide. That would react heavily with any Organics. There was no noticeable reaction. I did not try taking it and also putting it into a solution of acetic acid/ vinegar, because I felt that might be redundant.

Regardless, the mystery is definitely solved. What I said earlier is the answer. Just beware about mixing calcium chloride with chelated iron products like Brightwell Ferrion. It creates a solid made of calcium and iron and it drops out of solution. When I stopped doing that this tons of brown detritus stopped and became something more reasonable which was truly just a mixture of uneaten food and other mineral solids