Cyano or Diatom

[Nanz]

Im not sure if I have Cyano anymore but I still get this brown dust that covers my sandbed. Please help if you can.

I have a 75 gallon tank with 30 gallon sump/refugium.
S.G. 1.025
pH = 8.0 - 8.1
Temp 79.5
PO4, NH3, NO2 = 0
NO3 = 5ppm
Ca = 410
Alk = 9dKH
Mg = 1400
I have a DSB and 100lbs of live rock.
I run Kalkwasser through a reactor.
Phosban, Carbon and UV filtration.
ASM G1-X skimmer

I had a reddish brown slime on my sandbed 3 weeks ago and used Chemi-clean to remove it. I also prior to using chemi clean syphoned the contaminated sandbed all the way to the bottom. I know this is not a good thing to do but I guess I had to see for myself. Well after running the treatment everything cleared up and the red slime was removed. The next day this brown dust that looks like a diatom is covering my sandbed. Its brownish-green and not red at all. I could be wrong but it does not look like the red slime I had before.

I have tried everything to get rid of this brown dust. If I leave the lights off for 3 days its gone but its then back the following day with lights.

Am I still fighting cyano or is this a diatom issue? If it is diatom will it go away or is there something I need to do?

- I currently feed frozen mysis every other day.
- Feed pellets every day
- 10% water change weekly
- change filter sock every other day

----------------------
LiveStock
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Fish
-------------------
Powder brown tang
Gold striped maroon clown (Female)
Shrimp Goby
Lawmower Blenny
Fairy Wrasse

Inverts
-------------------
Coral Banded Shrimp
3 Peppermint Shrimp
Skunk Cleaner Shrimp
Pistol Shrimp
Sally lightfoot crab
5 scarlet hermit crabs
RBT Anemone
20 Nassarius snails
1 Queen conch
1 Fighting conch
5 Cerith snails
10 Astrea snails
10 Trochous snails
5 Nerite snails
20 Bumble bee snails

Corals
--------------
Torch
Bubble
Favia
Lobo
Frogspawn
Many zoo polyps
Toadstool
Yellow leather
sun coral

Cleaners
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Chiton
3 cleaner clams
10+ brittle stars
5+ spagetti worms
10+ bristle worms
and Lots of pods with Cheato in the refugium.

I think thats is about everything I can think of, hehe. Please help if you can I'm really sad about my tank right now

[MalHavoc]

brown dust is diatom. cyanobacteria is purple/red/black in colour. Are you doing water changes? If so, are you using tap water? If so, that's probably where your diatoms are coming from. tap water has silicate in it. Get RO or RO/DI water instead.

[Nanz]

Originally posted by MalHavoc
brown dust is diatom. cyanobacteria is purple/red/black in colour. Are you doing water changes? If so, are you using tap water? If so, that's probably where your diatoms are coming from. tap water has silicate in it. Get RO or RO/DI water instead.

I use RODI water with a TDS of < 1.0.
I use reef crystals for salt mix.

[dsn112]

Ive had a rust colored covering on my sand before, and I took it to a local marine biologist for testing. He ran it under a microscope and said it was a form of cyano bacteria. He told me to get a phosphate reactor, and within 2 weeks it was gone. Not sure why yours is there but thats what mine was. And it was not purple red or black.

[Nanz]

Originally posted by dsn112
Ive had a rust colored covering on my sand before, and I took it to a local marine biologist for testing. He ran it under a microscope and said it was a form of cyano bacteria. He told me to get a phosphate reactor, and within 2 weeks it was gone. Not sure why yours is there but thats what mine was. And it was not purple red or black.

Mine is more like a brown with green tint. Its gone at night and then comes back full force in the morning.

[Crimthann]

I'd probably blame the shifting around of the sand bed kicking up small amounts of ammonia into the water that the diatoms are chewing up. How long has it been doing this for? How long has the tank been up for?

Realistically if they're diatoms I'd probably just do a 10-15 gal water change and give it a week or two and see if it goes away.

[stingythingy45]

Did you do a large water change of at least 20% after 48 hrs. of treatment?Also I'm guessing that siphoning to the bottom of your sand bed could have killed some of the the anaerobic bacteria.Also exposing some bacteria to your treatment that you didn't want to kill.I'm going to say this is cyano as a result of dead bacteria fueling it.

[Nanz]

Originally posted by Crimthann
I'd probably blame the shifting around of the sand bed kicking up small amounts of ammonia into the water that the diatoms are chewing up. How long has it been doing this for? How long has the tank been up for?

Realistically if they're diatoms I'd probably just do a 10-15 gal water change and give it a week or two and see if it goes away.

Yea, thats what I thought also. The tank has been up for 6 months and the brown dust on sand started after the Chemi-Clean which was last week.

I did a 10% - 20% water change. The reason I say a range is because I do not have an accurate water volume. I have a 75gal tank, 100# LR, 5" DSB, 20 gal sump. I estimate that to be 75 - 85 gals of water. My salt container is 15gal which would be 20% of the 75gal water.

When doing a large water change what happens if the water goes below coral that are close to the surface? I never have drained water below the highest coral so that everything is always submerged.

[Crimthann]

Originally posted by Nanz

I did a 10% water change and should have done a 20%. I need to get a container to hold extra water for this. When doing a large water change what happens if the water goes below coral that are close to the surface? I never have drained water below the highest coral so that everything is always submerged.

You're alright if they're out of the water for a little while. The things that tend to get hurt by being out of the water are sponges. Just make sure that all of your new water is ready (temp and salinity) prior to draining the water, so you can refill it right away. You really don't want to leave them out for too long as they'll dry up. I also tend to turn off my lights if I'm changing enough water where the tips of some of my corals start poking out.

[nycsicktank]

i am also getting this from my fuge. i use ro water too.

tagging along.

[stingythingy45]

I just did a Chemi-clean treatment.Actually did the 20% water change last night.
Here's a thought,I had some brown stuff on my sand bed that looked like a light coating of diatoms.I did some research on this and posted this on here about a month ago.RC mod(water keeper)mentioned that it must be silcates added during my top-offs.I purchase my ro/di right now(soon to change).From what I've read,the first thing that begins to go in an ro/di unit is the DI.
This filter is responsible for silicate extraction.If the DI media is bad this will allow silicates into your system with top-offs,fueling a small diatom outbreak.Yes,even though your TDS is low.
My problem subsided,I would have to attribute it to the LFS changing filter media.The TDS was also low in that water as well.

[Crimthann]

Originally posted by stingythingy45
I just did a Chemi-clean treatment.Actually did the 20% water change last night.
Here's a thought,I had some brown stuff on my sand bed that looked like a light coating of diatoms.I did some research on this and posted this on here about a month ago.RC mod(water keeper)mentioned that it must be silcates added during my top-offs.I purchase my ro/di right now(soon to change).From what I've read,the first thing that begins to go in an ro/di unit is the DI.
This filter is responsible for silicate extraction.If the DI media is bad this will allow silicates into your system with top-offs,fueling a small diatom outbreak.Yes,even though your TDS is low.
My problem subsided,I would have to attribute it to the LFS changing filter media.The TDS was also low in that water as well.

Also very true. But I would think that chances are if her tank is 6 months old that the resin would be ok unless you have awful water . My resin is color changing when it starts to get used up which tends to be once a year. If you were doing water changes and top offs and you notice the diatoms later that day or the next then I would point at that.

In this case I'd assume it's something that got kicked up from the sand bed or like stingythingy45 said earlier that the Chemi-clean could have killed something that grazes on phytoplankton like the diatoms. I'd just give it a little bit to see if it goes away on its own. If it doesn't then explore other options like replacing the resin.

[dsn112]

Those "treatments" kill good and bad bacteria, and should rarely be used because of this. All of the good your ls and lr do can be eradicated with use of these treatments. What phosphate removal media do you use in your reactor. I am using Brightwell Phosphate R and it has helped a ton. RowaPhos is also excellent.

By the way, my brown cyano went away at night with the lights off and then raged back with the lights too. You may want to cut your lights a bit.

[Myrddraal]

I'm having a similar issue too. I had cyano, used a cyano killer that worked like a charm, and now have a brown/green film that grows on my sand during the day and is gone soon after lights out. I use RO/DI from a new (less than 6 mos) filter as well.

[Nanz]

Originally posted by stingythingy45
I just did a Chemi-clean treatment.Actually did the 20% water change last night.
Here's a thought,I had some brown stuff on my sand bed that looked like a light coating of diatoms.I did some research on this and posted this on here about a month ago.RC mod(water keeper)mentioned that it must be silcates added during my top-offs.I purchase my ro/di right now(soon to change).From what I've read,the first thing that begins to go in an ro/di unit is the DI.
This filter is responsible for silicate extraction.If the DI media is bad this will allow silicates into your system with top-offs,fueling a small diatom outbreak.Yes,even though your TDS is low.
My problem subsided,I would have to attribute it to the LFS changing filter media.The TDS was also low in that water as well.

Thats very interesting.. I will change my DI cartidge and see if that makes a difference. Thank you for the advice.

I hate to say but I'm glad I'm not the only one who experienced this problem.

[dileggi]

I had an issue with "red slime", or purple all over my sandbed. I did the same thing. Cleaned the sand all the way to the bottom with a siphon. It looked great and about a day or so later, everything came back with a browish/rusty color all over my sandbed.

Someone suggested to me to get a phosban reactor and it would help. I've been running the phosban for about two weeks now and it looks much better than it did before. It's still not gone yet, but it's getting better.