Grey/White and Hairy/Fuzzy stuff on Live Rocks

Posseidon · 05/10/2013, 03:09 PM

Need help in identifying and fighting the grey fuzzy stuff that's taking over my Live Rocks in the aquarium. The problem started two weeks ago.

Here's a pic:

Since I don't have a professional camera that can take good pic, here's one i downloaded from net. And the stuff on my rock looks exactly like it.

Here's another pic. Notice the hairy stuff at the edges on the underside.

It's not diatoms and not dinos. I had fought both in the past and know what they look like. This stuff is grey/white and grows anywhere. Even on the shaded or dark area. It's very lose and can easily be brushed off the rocks with a tooth brush. When my snail walks over the rock it just pushes it out of the way and the stuff easily comes off the rock and floats away.

Here's a small video of the stuff:

No matter how much I clean the rocks, it comes back quickly.

NO3 - 10
PO4 - undetectable
SiO2 - undetectable
Ph - 8.2 (approx)

I run Bio-pellets (outflow from reactor goes to Protein Skimmer power head inlet) and RowaPhos in my sump. Have been using RowaCarbon for last three days.

Posseidon · 05/11/2013, 03:16 PM

I thought RC is one of the most active forums in this hobby. Is there no one who could help me battle this stuff? All experienced reefers, plz comment. This stuff is worrying me and ruins the look.

Thnx.

ridetheducati · 05/11/2013, 04:48 PM

Did you try the search feature?

greg1786 · 05/11/2013, 04:52 PM

The exact same thing happened in my friends predator sw tank three days ago. We tried searching rc archives and google and cant find an ID anywhere either. Hopefully someone will chime in who knows something

ridetheducati · 05/11/2013, 07:30 PM

The growth that you are experiencing is due to excess bacteria. Common with new tanks carbon dosing. Increase CUC and continue to maintain stable quality water parameters and it will subside.

Strongly recommend that you research carbon dosing so you become aware of the pitfalls and nuances of carbon dosing.

tatuaje08 · 05/11/2013, 10:28 PM

I have this stuff too and don't carbon dose. Hoping someone can give more details about what this stuff is and what cuc will help get rid of it.

Holyhands22 · 05/11/2013, 10:53 PM

ImageUploadedByTapatalk1368334399.455412.jpg

This is what mine looks like in my predator tank.

Posseidon · 05/12/2013, 08:24 AM

I've googled so much too. No luck to pin point the ID. I found a few threads in several forums including RC, but none of them end with any conclusion. Even the ppl who experienced it didn't come back to update the thread.

I hope we all do our share in fighting this stuff and post results. And hopefully we end this thread with a conclusion and possibly a fix.

Someone I know told me that this could be calcium carbonate precipitation. And its filamentous and not hard because of low Mg. What's your opinion?

I'll do this in steps. Two inputs so far:

1) Percipitation
2) Excess bacteria.

For (1), I'll test Mg today and bring it in range. And observe for a couple of days.

Then, I'll try to tackle (2) by taking the Bio-Pellets reactor offline for a day or two. By the way, i did feel like it could be excess bacteria. So, just to make sure that the Bio-pellets has not leeched a lot of carbon in water column, I used RowaCarbon for 4 days. Didn't make any difference.

tatuaje08 · 05/12/2013, 08:28 AM

My mg is always 1350+.

crypteria · 05/12/2013, 08:43 AM

To the OP: I was told that they are harmless Foraminiferans. Hope this helps.

Austin

ridetheducati · 05/12/2013, 09:01 AM

Quote:

Originally Posted by Posseidon

Then, I'll try to tackle (2) by taking the Bio-Pellets reactor offline for a day or two. By the way, i did feel like it could be excess bacteria. So, just to make sure that the Bio-pellets has not leeched a lot of carbon in water column, I used RowaCarbon for 4 days. Didn't make any difference.

Pellets are the carbon (food) source. Take the pellets offline for a few weeks and see whether the growth fades away.

RowaCarbon is granular activated carbon, which is has nothing to do with carbon dosing.

Posseidon · 05/12/2013, 02:28 PM

Quote:

Originally Posted by ridetheducati

Pellets are the carbon (food) source. Take the pellets offline for a few weeks and see whether the growth fades away.

RowaCarbon is granular activated carbon, which is has nothing to do with carbon dosing.

Ok. You're probably right. A couple of weeks of observation maybe needed instead of a few days.

I had used activated carbon to capture any organic carbon from water itself. So that carbon is available only in the reactor and the bacteria could colonize in the reactor intead of the display tank.

Posseidon · 05/12/2013, 03:38 PM

Quote:

Originally Posted by crypteria

To the OP: I was told that they are harmless Foraminiferans. Hope this helps.

Austin

Harmless is good. Well, all corals and fish seem to be doing well.

But this stuff looks so bad. If it is Foraminiferans, how do i get rid of it?

Posseidon · 05/13/2013, 01:36 PM

I was not using any additives for quite some time. I guess I should have. I got the Salifert Magnesium test kit. And Oops! It was 1230 ppm.

My Ca is low too at 380 and Alk. is at 9.

I'll bring it in range before dosing Ca and KH. Btw, I do have Purple Up but haven't used it in this tank. Shall I use it to increase Ca and Carbonates?

haze152 · 05/13/2013, 01:41 PM

I would take carbon out for a couple days. And see what happens

SushiGirl · 05/13/2013, 04:29 PM

Quote:

Originally Posted by ridetheducati

The growth that you are experiencing is due to excess bacteria. Common with new tanks carbon dosing. Increase CUC and continue to maintain stable quality water parameters and it will subside.

We had this issue when we set our 55 up. We didn't and don't carbon dose.
Not sure why you feel you must eradicate it. In a couple of months it will only be in the dark areas, then one day it will be gone.

Edit: Why remove the carbon? We don't have this issue & we run carbon in a reactor.
Another Edit: Don't bother with purple up, it's just calcium carbonate sand and will not dissolve in your tank. If you need to raise calcium, get mag & alk in line then figure out if you need to dose calcium to raise it.

Posseidon · 05/16/2013, 09:51 AM

Thnx for the advices. This is likely bacterial bloom based on most opinions provided. So, I just have to observe which move could make my tank look neat again.

I'll try some frequent water changes with Red Sea Coral Pro Salt. That should fix my Mg, Ca and Alk levels gradually. If not I'll start dosing. I'll observe if it has any impact. Besides, I need to bring them in range for my corals anyway.

I'll post the results.

crypteria · 05/16/2013, 11:04 AM

In my tanks they are in low light areas and recede with greater light intensity. Sometimes they are just part of the cycle, another wave of life forms that come and go...

tanked37 · 05/16/2013, 11:41 AM

As a solid preventative measure for a good handful of things (including bacterial blooms) adding a UV sterilizer would only help. I have a 25W aqua-uv unit on my 90 gallon. Runs 24-7.

Posseidon · 05/22/2013, 12:07 PM

Update.

I cleaned up the stuff with toothbrush. I know, tedious! I couldn't cover all the rocks though. And then most of the stuff was floating around. I immediately did a 20% water change. That brought my Ca and Mg levels close to normal range. I then dosed some Mg and brought it in right range. I also added two more turbo snails to clean up the rocks.

So far, the growth of this stuff seems to have stopped. And it looks better. But it hasn't gone yet.

NO3 - 5ppm
PO4 - undetectable

Ca - 420 ppm
Mg - 1420 ppm
Alk - 10

I don't have any more ideas now, but to wait and see if it reduces by itself.

If anyone has any other suggestions for me, please let me know.

Posseidon · 05/23/2013, 10:35 AM

Hi tanked,

I used to run UV, but stopped because I wanted to setup the BP Reactor. Will starting it now be of help?

brandon429 · 05/23/2013, 10:43 AM

The only direct action taken on it leaves portions on the rocks to regrow, thats an issue. All other recommendations are about taking indirect action, through the water column. You would have been massively surprised to see the outcome if you would have added a little peroxide to that toothbrush when you scrubbed. That actually kills the organism in questions regardless of what it is. the current method of physical removal doesnt address holdfasts in the rock, if any, and it also disperses fragments around the tank to regrow typically.

in cases like these where we aren't even sure of the ID it really helps to consider simply killing the target a few times repeated, instead of just removing it without a biocidal kill. You might just glance over this idea and move on to more nutrient stripping which is the common approach, but if you want to see about a thousand pictures like yours and of worse situations we've fixed with a toothbrush and peroxide, see the thread on page two nanos forum pico reef pest algae problem challenge. it'll surprise ya

brandon429 · 05/23/2013, 10:46 AM

its wrong to look at invader control as strictly a long term approach. The most common statement made nowadays is that if you aren't stripping phosphates, you are using a bandaid. That doesnt call into question invaders that need treating that are nutrient independent...meaning you'll bleach your corals long before you nutrient starve red brush algae, invasive macroalgae, bryopsis, dinoflagellates etc.

proponents of algal turf filters have shown cure pics from using their angle, thats another to consider.
the only reason I dont use that is because again this way is faster in small tanks, the effort you must have used in dismantling and cleaning your rocks must have taken quite some time comparatively.

Long term results are what you strive for after a true initial kill, to prevent regrowth. Using preventatives as algae removers is something that's very wrong with todays algae control approaches. using peroxide as a little boost is harmless to try as you've already done the initial external scrubbing. It has a chance of stopping the growth on first pass, we have pics of that in the thread. the more likely outcome is that its an -excellent- control method to use occasionally until one of the preventatives mentioned does its job. thats how I use it, every few months and then nothing else is required for my tank to be algae free. plus I get to be care-free of phosphate levels and all the tedious work ascribed to controlling it, since the every few months treatment zap keeps my tank clean in the meantime. I dont see how further stripping your tank of nutrients is safer. you should keep the nutrient levels you have now and find the clean up crew that works as your preventative. the one thing that is certain is that you can be rid of this stuff pretty easily. if you have questions about the bacteria on your rocks etc while treating, see our thread. harmless. it is perfectly ok to manage phosphates as an end-all approach to algae care its just not the only way. I use this method because its less work on my tank and actually better at keeping things algae free, as you can see its possible to still get growth in the face of great nutrient params.

The ocean gets algae in perfect (what we would test as) waters when grazers are removed, that says something about indirect only control. there are pics of this same type growth being cleaned in our big thread just can't remember what page, too many now.

brandon429 · 05/23/2013, 11:08 AM

fwiw, I think you might have a strain of bryozoans. google those and see what you think.

Posseidon · 05/23/2013, 12:03 PM

Thanks for all your inputs. Appreciate it.

This thing is on every rock!.. The target approach with toothbrush and peroxide might take forever. And may also kill all the coralline algae on the rocks. Not to mention complications of corals on them.

But your idea is good for controlling nuisance algae that's localized on rocks.

I had a big dino issue and recently came back from tearing down my tank. I literally took the pain of taking all the rocks out, cleaning them with toothbrush as much as possible and then dumping them in a blue bucket with 3/4th fresh SW and low nutrients. I couldn't put completely new water, because I didn't want to lose the beneficial bacteria and there were some nice blue sponge attached to the rocks. Taking them out would only tear them. And well, blue sponge does not like ULN water.

The blue bucket was lit with low watt lights to keep the coralline alive on the rocks. I put all my corals in another quarantine tank with argonite sand base and some filters. They were closely packed but not to the extent to threaten each other. My display tank was bare with only fishes in it and a couple of Live Rocks. I kept the DT in darkness and only turned on the lights while feeding.

Kept the above setup for more than a month. All dinos were dead. I added BP Reactor to the DT in the third week and ran that for two weeks in darkness. After about a month of BP usage, the Nitrates didn't seem to reduce. So, I upped the pellets in the reactor with twice as much as recommended. And then, they finally started reducing Nitrates. And I got all livestock and rocks back in DT.

It was all good for about a month. All clean and nice with clear water. However, I was a little busy with work and didn't get to do water change for a month. And then this stuff showed up on the rocks. And a few days later, I had some heavy CaCO3 precipitation on my tank glass and a little on rocks.

I then reduced pellets in the reactor to the recommended amount, thinking that this could be excess bacterial growth. It couldn't be a bacterial bloom, since my water did not go cloudy. It wasn't pristine clear but not cloudy either.

The precipitation was due to low Mg. So, I cleaned the rocks with the toothbrush in the tank and immediately a 20% water change. And brought all water parameters in check. So far, the growth of this stuff seems to have slowed down a lot.

Some people say to just wait it out and it'll reduce. I don't know if it was the time or the water change that slowed it's growth.

Now, even the slightest thought of tearing down my tank again freaks me out! I can't go through that again!! I need to find a way of dealing with this within the tank.

The good part is that it is harmless. Doesn't bother the fish or the corals. So, I don't have to rush into drastic measures. I was seeking some time-tested and proven approach to deal with this.

There are not many Reef Tank pics on google for bryozoans. It's hard to say if it's the same stuff. I'll still read about it and let you know my opinion.

All I can say is that this stuff is very light and fragile. Easily comes off the rocks. It's like Volcano dust shown in movies (all over the place but easily brushed off).

The funny part is that, there are quite a few reefers out there who've experienced this. But no one still has a clue nor an update of how they took care of it.

RC is one of the biggest forums in this hobby. If I don't get any help here, don't know where I'll find any.

05/10/2013, 03:09 PM	#1
Posseidon Registered Member Join Date: May 2013 Posts: 138	Grey/White and Hairy/Fuzzy stuff on Live Rocks Need help in identifying and fighting the grey fuzzy stuff that's taking over my Live Rocks in the aquarium. The problem started two weeks ago. Here's a pic: Since I don't have a professional camera that can take good pic, here's one i downloaded from net. And the stuff on my rock looks exactly like it. Here's another pic. Notice the hairy stuff at the edges on the underside. It's not diatoms and not dinos. I had fought both in the past and know what they look like. This stuff is grey/white and grows anywhere. Even on the shaded or dark area. It's very lose and can easily be brushed off the rocks with a tooth brush. When my snail walks over the rock it just pushes it out of the way and the stuff easily comes off the rock and floats away. Here's a small video of the stuff: No matter how much I clean the rocks, it comes back quickly. NO3 - 10 PO4 - undetectable SiO2 - undetectable Ph - 8.2 (approx) I run Bio-pellets (outflow from reactor goes to Protein Skimmer power head inlet) and RowaPhos in my sump. Have been using RowaCarbon for last three days.

05/11/2013, 04:48 PM	#3
ridetheducati 20 and Over Club Join Date: Sep 2000 Location: Bowie, MD Posts: 2,968	Did you try the search feature? __________________ "Send more paramedics" Current Tank Info: 300g DD, SPS dominated, Apex, Tunze 6125s, ATB 1050, 400w MH, and Geo 618 Ca Reactor

05/11/2013, 07:30 PM	#5
ridetheducati 20 and Over Club Join Date: Sep 2000 Location: Bowie, MD Posts: 2,968	The growth that you are experiencing is due to excess bacteria. Common with new tanks carbon dosing. Increase CUC and continue to maintain stable quality water parameters and it will subside. Strongly recommend that you research carbon dosing so you become aware of the pitfalls and nuances of carbon dosing. __________________ "Send more paramedics" Current Tank Info: 300g DD, SPS dominated, Apex, Tunze 6125s, ATB 1050, 400w MH, and Geo 618 Ca Reactor Last edited by ridetheducati; 05/11/2013 at 07:36 PM.

05/23/2013, 10:46 AM	#23
brandon429 Registered Member. Join Date: Feb 2002 Posts: 3,460	its wrong to look at invader control as strictly a long term approach. The most common statement made nowadays is that if you aren't stripping phosphates, you are using a bandaid. That doesnt call into question invaders that need treating that are nutrient independent...meaning you'll bleach your corals long before you nutrient starve red brush algae, invasive macroalgae, bryopsis, dinoflagellates etc. proponents of algal turf filters have shown cure pics from using their angle, thats another to consider. the only reason I dont use that is because again this way is faster in small tanks, the effort you must have used in dismantling and cleaning your rocks must have taken quite some time comparatively. Long term results are what you strive for after a true initial kill, to prevent regrowth. Using preventatives as algae removers is something that's very wrong with todays algae control approaches. using peroxide as a little boost is harmless to try as you've already done the initial external scrubbing. It has a chance of stopping the growth on first pass, we have pics of that in the thread. the more likely outcome is that its an -excellent- control method to use occasionally until one of the preventatives mentioned does its job. thats how I use it, every few months and then nothing else is required for my tank to be algae free. plus I get to be care-free of phosphate levels and all the tedious work ascribed to controlling it, since the every few months treatment zap keeps my tank clean in the meantime. I dont see how further stripping your tank of nutrients is safer. you should keep the nutrient levels you have now and find the clean up crew that works as your preventative. the one thing that is certain is that you can be rid of this stuff pretty easily. if you have questions about the bacteria on your rocks etc while treating, see our thread. harmless. it is perfectly ok to manage phosphates as an end-all approach to algae care its just not the only way. I use this method because its less work on my tank and actually better at keeping things algae free, as you can see its possible to still get growth in the face of great nutrient params. The ocean gets algae in perfect (what we would test as) waters when grazers are removed, that says something about indirect only control. there are pics of this same type growth being cleaned in our big thread just can't remember what page, too many now. Last edited by brandon429; 05/23/2013 at 11:01 AM.

05/11/2013, 03:16 PM	#2
Posseidon Registered Member Join Date: May 2013 Posts: 138	I thought RC is one of the most active forums in this hobby. Is there no one who could help me battle this stuff? All experienced reefers, plz comment. This stuff is worrying me and ruins the look. Thnx.

05/11/2013, 04:52 PM	#4
greg1786 Registered Member Join Date: Jul 2012 Location: Baltimore md Posts: 1,241	The exact same thing happened in my friends predator sw tank three days ago. We tried searching rc archives and google and cant find an ID anywhere either. Hopefully someone will chime in who knows something

05/11/2013, 10:28 PM	#6
tatuaje08 Registered Member. Join Date: May 2013 Location: tempe, az Posts: 867	I have this stuff too and don't carbon dose. Hoping someone can give more details about what this stuff is and what cuc will help get rid of it.

05/11/2013, 10:53 PM	#7
Holyhands22 Registered Member Join Date: Aug 2012 Location: Baltimore,md Posts: 152	ImageUploadedByTapatalk1368334399.455412.jpg This is what mine looks like in my predator tank.

05/12/2013, 08:24 AM	#8
Posseidon Registered Member Join Date: May 2013 Posts: 138	I've googled so much too. No luck to pin point the ID. I found a few threads in several forums including RC, but none of them end with any conclusion. Even the ppl who experienced it didn't come back to update the thread. I hope we all do our share in fighting this stuff and post results. And hopefully we end this thread with a conclusion and possibly a fix. Someone I know told me that this could be calcium carbonate precipitation. And its filamentous and not hard because of low Mg. What's your opinion? I'll do this in steps. Two inputs so far: 1) Percipitation 2) Excess bacteria. For (1), I'll test Mg today and bring it in range. And observe for a couple of days. Then, I'll try to tackle (2) by taking the Bio-Pellets reactor offline for a day or two. By the way, i did feel like it could be excess bacteria. So, just to make sure that the Bio-pellets has not leeched a lot of carbon in water column, I used RowaCarbon for 4 days. Didn't make any difference.

05/12/2013, 08:28 AM	#9
tatuaje08 Registered Member. Join Date: May 2013 Location: tempe, az Posts: 867	My mg is always 1350+.

05/12/2013, 08:43 AM	#10
crypteria Registered Member Join Date: Aug 2012 Location: Jacksonville, FL Posts: 53	To the OP: I was told that they are harmless Foraminiferans. Hope this helps. Austin

05/13/2013, 01:36 PM	#14
Posseidon Registered Member Join Date: May 2013 Posts: 138	I was not using any additives for quite some time. I guess I should have. I got the Salifert Magnesium test kit. And Oops! It was 1230 ppm. My Ca is low too at 380 and Alk. is at 9. I'll bring it in range before dosing Ca and KH. Btw, I do have Purple Up but haven't used it in this tank. Shall I use it to increase Ca and Carbonates?

05/13/2013, 01:41 PM	#15
haze152 Registered Member Join Date: May 2013 Posts: 115	I would take carbon out for a couple days. And see what happens

05/16/2013, 09:51 AM	#17
Posseidon Registered Member Join Date: May 2013 Posts: 138	Thnx for the advices. This is likely bacterial bloom based on most opinions provided. So, I just have to observe which move could make my tank look neat again. I'll try some frequent water changes with Red Sea Coral Pro Salt. That should fix my Mg, Ca and Alk levels gradually. If not I'll start dosing. I'll observe if it has any impact. Besides, I need to bring them in range for my corals anyway. I'll post the results.

05/16/2013, 11:04 AM	#18
crypteria Registered Member Join Date: Aug 2012 Location: Jacksonville, FL Posts: 53	In my tanks they are in low light areas and recede with greater light intensity. Sometimes they are just part of the cycle, another wave of life forms that come and go...

05/16/2013, 11:41 AM	#19
tanked37 Registered Member Join Date: Nov 2012 Posts: 262	As a solid preventative measure for a good handful of things (including bacterial blooms) adding a UV sterilizer would only help. I have a 25W aqua-uv unit on my 90 gallon. Runs 24-7.

05/22/2013, 12:07 PM	#20
Posseidon Registered Member Join Date: May 2013 Posts: 138	Update. I cleaned up the stuff with toothbrush. I know, tedious! I couldn't cover all the rocks though. And then most of the stuff was floating around. I immediately did a 20% water change. That brought my Ca and Mg levels close to normal range. I then dosed some Mg and brought it in right range. I also added two more turbo snails to clean up the rocks. So far, the growth of this stuff seems to have stopped. And it looks better. But it hasn't gone yet. NO3 - 5ppm PO4 - undetectable Ca - 420 ppm Mg - 1420 ppm Alk - 10 I don't have any more ideas now, but to wait and see if it reduces by itself. If anyone has any other suggestions for me, please let me know.

05/23/2013, 10:35 AM	#21
Posseidon Registered Member Join Date: May 2013 Posts: 138	Hi tanked, I used to run UV, but stopped because I wanted to setup the BP Reactor. Will starting it now be of help?

05/23/2013, 10:43 AM	#22
brandon429 Registered Member. Join Date: Feb 2002 Posts: 3,460	The only direct action taken on it leaves portions on the rocks to regrow, thats an issue. All other recommendations are about taking indirect action, through the water column. You would have been massively surprised to see the outcome if you would have added a little peroxide to that toothbrush when you scrubbed. That actually kills the organism in questions regardless of what it is. the current method of physical removal doesnt address holdfasts in the rock, if any, and it also disperses fragments around the tank to regrow typically. in cases like these where we aren't even sure of the ID it really helps to consider simply killing the target a few times repeated, instead of just removing it without a biocidal kill. You might just glance over this idea and move on to more nutrient stripping which is the common approach, but if you want to see about a thousand pictures like yours and of worse situations we've fixed with a toothbrush and peroxide, see the thread on page two nanos forum pico reef pest algae problem challenge. it'll surprise ya

05/23/2013, 11:08 AM	#24
brandon429 Registered Member. Join Date: Feb 2002 Posts: 3,460	fwiw, I think you might have a strain of bryozoans. google those and see what you think.

05/23/2013, 12:03 PM	#25
Posseidon Registered Member Join Date: May 2013 Posts: 138	Thanks for all your inputs. Appreciate it. This thing is on every rock!.. The target approach with toothbrush and peroxide might take forever. And may also kill all the coralline algae on the rocks. Not to mention complications of corals on them. But your idea is good for controlling nuisance algae that's localized on rocks. I had a big dino issue and recently came back from tearing down my tank. I literally took the pain of taking all the rocks out, cleaning them with toothbrush as much as possible and then dumping them in a blue bucket with 3/4th fresh SW and low nutrients. I couldn't put completely new water, because I didn't want to lose the beneficial bacteria and there were some nice blue sponge attached to the rocks. Taking them out would only tear them. And well, blue sponge does not like ULN water. The blue bucket was lit with low watt lights to keep the coralline alive on the rocks. I put all my corals in another quarantine tank with argonite sand base and some filters. They were closely packed but not to the extent to threaten each other. My display tank was bare with only fishes in it and a couple of Live Rocks. I kept the DT in darkness and only turned on the lights while feeding. Kept the above setup for more than a month. All dinos were dead. I added BP Reactor to the DT in the third week and ran that for two weeks in darkness. After about a month of BP usage, the Nitrates didn't seem to reduce. So, I upped the pellets in the reactor with twice as much as recommended. And then, they finally started reducing Nitrates. And I got all livestock and rocks back in DT. It was all good for about a month. All clean and nice with clear water. However, I was a little busy with work and didn't get to do water change for a month. And then this stuff showed up on the rocks. And a few days later, I had some heavy CaCO3 precipitation on my tank glass and a little on rocks. I then reduced pellets in the reactor to the recommended amount, thinking that this could be excess bacterial growth. It couldn't be a bacterial bloom, since my water did not go cloudy. It wasn't pristine clear but not cloudy either. The precipitation was due to low Mg. So, I cleaned the rocks with the toothbrush in the tank and immediately a 20% water change. And brought all water parameters in check. So far, the growth of this stuff seems to have slowed down a lot. Some people say to just wait it out and it'll reduce. I don't know if it was the time or the water change that slowed it's growth. Now, even the slightest thought of tearing down my tank again freaks me out! I can't go through that again!! I need to find a way of dealing with this within the tank. The good part is that it is harmless. Doesn't bother the fish or the corals. So, I don't have to rush into drastic measures. I was seeking some time-tested and proven approach to deal with this. There are not many Reef Tank pics on google for bryozoans. It's hard to say if it's the same stuff. I'll still read about it and let you know my opinion. All I can say is that this stuff is very light and fragile. Easily comes off the rocks. It's like Volcano dust shown in movies (all over the place but easily brushed off). The funny part is that, there are quite a few reefers out there who've experienced this. But no one still has a clue nor an update of how they took care of it. RC is one of the biggest forums in this hobby. If I don't get any help here, don't know where I'll find any.