What is this white growth?

[Lifeisgood]

I upgraded the size tank when we moved 2 1/2 months ago.  Added some new pool filter sand and capped it with the old substrate—mulm and all.  Used same plants, rocks and driftwood from old tank, hoping to keep the beneficial bacteria alive.

I do not like to disturb the substrate much because I want the substrate to be enriched to feed the plant roots.

I have been watching this white growth develop and hoped that it was benign and maybe useful for the ecosystem of the tank.  But maybe I am letting things get carried too far in this direction?

Can anyone tell me what this is and if I need to intervene and remove it for the health of my fish?

[Guppysnail]

This looks like normal biofilm etc in a new setup just a lot more than I’ve ever seen. I’ve had it even in tanks with established filters etc that I moved to a larger tank with new substrate. I however have never seen that much of it. Maybe something in the new sand…totally guessing there. it’s normal goes away after about a month for me but you do have quite a bit and it’s hanging around so it may be something more. Hopefully someone can give you more info. 

[Lifeisgood]

On 11/11/2021 at 6:32 PM, Guppysnail said:

This looks like normal biofilm etc in a new setup just a lot more than I’ve ever seen. I’ve had it even in tanks with established filters etc that I moved to a larger tank with new substrate. I however have never seen that much of it. Maybe something in the new sand…totally guessing there. it’s normal goes away after about a month for me but you do have quite a bit and it’s hanging around so it may be something more. Hopefully someone can give you more info. 

Thank you for the input!  It seems like I have seen smaller amounts before that disappeared after a while—but this seemed like a lot and I started to worry.  Hoping someone will let me know if it is something I need to address.  All fish and invertebrates seem healthy and happy.

[eatyourpeas]

Sometimes that can happen when the substrate is disturbed. It is not harmful and will eventually go away on its own.

[gardenman]

It looks like a fungus to me. If you have any Pimafix, it should clear it up in short order. Fungus usually occurs when you have an undiscovered dead fish or uneaten food. It can choke out and kill plants and some can even become toxic to fish, so clearing it up is a good idea. Pimafix (or some other anti-fungal) is a good option. Some water changes and looking for the source are good options also. I've dealt with big fungus issues in the past, so I keep some Pimafix on hand. A year or two ago I had an issue with it in my thirty high. It choked out several plants before I got it under control. It can be a real nuisance.

[Lifeisgood]

On 11/13/2021 at 8:04 AM, gardenman said:

It looks like a fungus to me. If you have any Pimafix, it should clear it up in short order. Fungus usually occurs when you have an undiscovered dead fish or uneaten food. It can choke out and kill plants and some can even become toxic to fish, so clearing it up is a good idea. Pimafix (or some other anti-fungal) is a good option. Some water changes and looking for the source are good options also. I've dealt with big fungus issues in the past, so I keep some Pimafix on hand. A year or two ago I had an issue with it in my thirty high. It choked out several plants before I got it under control. It can be a real nuisance.

Gardenman, thought I would give you an update on the mystery of the white growth on my substrate:  First, I decided to manually try to remove it by aggressively using a syphon.  It grew back in a week.  The sulfur smell increased with the amount of white growth.

Then I bought Pimafix and siphoned the aggressively removing quite a bit of the sand substrate where I saw the growth.  Then treated the water for seven days as directed on the Pimafix bottle.

I was very disappointed to see that it was growing again under the drift wood and toward the back of the tank—not where I had seen the white growth and siphoned before.

Then I noticed a strange thing.  The fist sized white rock that used to be in the back of the tank had melted into a few slender chips!  I haven’t had it analyzed yet—but perhaps this was the cause of the white growth?!  

It looked like a fungus.  It smelled like sulfur and was soft and tufts of it floated easily when disturbed with my fingers.  No fish died.  When the growth was at it’s worst the fish were not very active and worked their gills faster.  That was when I began to attack the problem.

I thought the rock was quartzite but obviously it was softer.  Calcite perhaps?  Any ideas?  What else would melt like that?  It has only been in my tank since the beginning of October.  From a fist sized chunk to chips in two months.🤷‍♀️

I have cleaned the areas affected to the bare bottom of the tank.  I will have to add substrate when I am sure the problem is solved.  How strange.  

[Lifeisgood]

On 11/11/2021 at 6:32 PM, Guppysnail said:

This looks like normal biofilm etc in a new setup just a lot more than I’ve ever seen. I’ve had it even in tanks with established filters etc that I moved to a larger tank with new substrate. I however have never seen that much of it. Maybe something in the new sand…totally guessing there. it’s normal goes away after about a month for me but you do have quite a bit and it’s hanging around so it may be something more. Hopefully someone can give you more info. 

Guppysnail, I appreciated your feedback early on.  I thought you might be intrigued by what I have discovered since then.  Check out what I wrote to Gardenman.  I think it was a melted mineral of somekind.

[Guppysnail]

That is fascinating.  I have never heard of a rock melting in an aquarium. I’m glad you figured out what the white stuff was and that it caused no harm. 

[Lifeisgood]

On 12/23/2021 at 5:43 AM, Guppysnail said:

That is fascinating.  I have never heard of a rock melting in an aquarium. I’m glad you figured out what the white stuff was and that it caused no harm. 

After a discussion about rocks with some folks in the General topic section—we came to the conclusion that the white rock was gypsum.  It is soft enough to scratch with a fingernail, it contains sulfur and can dissolve in water.  So we can add gypsum to the list of rocks to not put in our aquariums and we now know what it will do.

We also now know that we should ask about a person’s rocks when they are struggling with a “white fungus” growth on their substrate that smells like sulfur.

I love being part of this community!  I learn so much! 😊

Thanks for your part.

[Lifeisgood]

On 11/13/2021 at 8:04 AM, gardenman said:

It looks like a fungus to me. If you have any Pimafix, it should clear it up in short order. Fungus usually occurs when you have an undiscovered dead fish or uneaten food. It can choke out and kill plants and some can even become toxic to fish, so clearing it up is a good idea. Pimafix (or some other anti-fungal) is a good option. Some water changes and looking for the source are good options also. I've dealt with big fungus issues in the past, so I keep some Pimafix on hand. A year or two ago I had an issue with it in my thirty high. It choked out several plants before I got it under control. It can be a real nuisance.

Thank you for your interest in helping me with the white growth.  The problem turned out to be caused by a gypsum rock in my tank.  It can dissolve in water, it has sulfur in it and can be scratched with your fingernail.  And apparently will crystalize in a soft form on substrate that kills plants, stinks like sulfur and looks like a fungus.
 

Now we know!😊

On 11/13/2021 at 1:00 AM, eatyourpeas said:

Sometimes that can happen when the substrate is disturbed. It is not harmful and will eventually go away on its own.

Thank you for your interest in trying to help me figure out how to deal with the weird growth I was struggling with in my aquarium.  It turns out it was caused by a gypsum rock that was melting in my tank.  Who would have thunk? 😅