White Stringy Slime

RhiD08

Community Member
View Badges
Joined
Oct 28, 2020
Messages
80
Reaction score
45
Location
ontario
Rating - 0%
0   0   0
Hi!

I have a Fluval Sea Evo 13.5 gallon tank that’s been up and running for 7 months. I’ve had no issues with the tank until about a month ago when I decided to dose Red Sea Reef Energy AB+. My nitrates were bottoming out and my corals weren’t growing but I wanted to avoid dosing anything so I tried reducing the volume and frequency of my water changes. When this didn’t work, I decided to dose Red Sea instead of just nitrates to give the corals something extra. I only dosed 1/4 of the recommended, so 1 ml, twice in a week, on Sunday and Wednesday. After this, I started to notice diatoms on my sand so I stopped dosing and haven’t used it since.

However, the last couple of days I’ve noticed a stringy white/clear slime in my tank on the walls, rocks, and even corals. It’s also in my filter chambers. I assumed it was just some sort of algae and that it would clear up however my filter floss has been getting clogged and overflowing even though it appears clean. When I changed the filter floss, it feels super slimy. I tried researching it and read that it’s a type of bacteria that is usually due to carbon dosing or some time of carbon input near your tank. However, I don’t carbon dose and nothing has changed or been used near the tank recently. I measured my parameters and my nitrates are bottomed out although they were around 2 ppm before this started so I’m assuming the bacteria are consuming it. My phosphates are a bit high at 0.1 ppm but I haven’t done a weekly water change yet and they usually sit around 0.05 ppm.

I should also mention that a couple of weeks ago I used Salifert Flatworm eXit to treat my tank of flatworms. The treatment did not work and I haven’t used it since. I added chemipure blue nano right after medicating the tank as well.

My parameters are:
Ammonia = 0
Nitrite = 0
Nitrate = 0 ppm
Phosphates = 0.1 ppm
Salinity = 35 ppt
Temperature = 78 degrees Fahrenheit
Calcium = 350
Magnesium = 1350
TDS = 0

I should also mention that I use RO/DI water and Red Sea Coral Pro Salt.

Any advice on the clearing this bacteria and the diatoms would be much appreciated.
IMG_8285.jpeg
IMG_8443.jpeg
IMG_8451.jpeg
IMG_8449.jpeg
 

Dan_P

7500 Club Member
View Badges
Joined
Sep 21, 2018
Messages
9,876
Reaction score
9,741
Rating - 0%
0   0   0
Hi!

I have a Fluval Sea Evo 13.5 gallon tank that’s been up and running for 7 months. I’ve had no issues with the tank until about a month ago when I decided to dose Red Sea Reef Energy AB+. My nitrates were bottoming out and my corals weren’t growing but I wanted to avoid dosing anything so I tried reducing the volume and frequency of my water changes. When this didn’t work, I decided to dose Red Sea instead of just nitrates to give the corals something extra. I only dosed 1/4 of the recommended, so 1 ml, twice in a week, on Sunday and Wednesday. After this, I started to notice diatoms on my sand so I stopped dosing and haven’t used it since.

However, the last couple of days I’ve noticed a stringy white/clear slime in my tank on the walls, rocks, and even corals. It’s also in my filter chambers. I assumed it was just some sort of algae and that it would clear up however my filter floss has been getting clogged and overflowing even though it appears clean. When I changed the filter floss, it feels super slimy. I tried researching it and read that it’s a type of bacteria that is usually due to carbon dosing or some time of carbon input near your tank. However, I don’t carbon dose and nothing has changed or been used near the tank recently. I measured my parameters and my nitrates are bottomed out although they were around 2 ppm before this started so I’m assuming the bacteria are consuming it. My phosphates are a bit high at 0.1 ppm but I haven’t done a weekly water change yet and they usually sit around 0.05 ppm.

I should also mention that a couple of weeks ago I used Salifert Flatworm eXit to treat my tank of flatworms. The treatment did not work and I haven’t used it since. I added chemipure blue nano right after medicating the tank as well.

My parameters are:
Ammonia = 0
Nitrite = 0
Nitrate = 0 ppm
Phosphates = 0.1 ppm
Salinity = 35 ppt
Temperature = 78 degrees Fahrenheit
Calcium = 350
Magnesium = 1350
TDS = 0

I should also mention that I use RO/DI water and Red Sea Coral Pro Salt.

Any advice on the clearing this bacteria and the diatoms would be much appreciated.
IMG_8285.jpeg
IMG_8443.jpeg
IMG_8451.jpeg
IMG_8449.jpeg
Some of this looks like dying hair algae. The stuff on the wire looks like ordinary multiple species microorganism growth. Without a microscope, identifying this stuff is tricky
 

Gone Reefin’

Active Member
View Badges
Joined
Mar 22, 2025
Messages
358
Reaction score
493
Location
Illinois
Rating - 0%
0   0   0
The slimy feel and white strings is indicative of a bacterial bloom. I don’t believe these blooms are normal in an established tank unless you are carbon dosing, exactly as you read. If I had to guess, flatworm exit impacted your biome and a bacterial strain is outcompeting and blooming.

If a bloom, ride it out for several days.
 
OP
OP
R

RhiD08

Community Member
View Badges
Joined
Oct 28, 2020
Messages
80
Reaction score
45
Location
ontario
Rating - 0%
0   0   0
Some of this looks like dying hair algae. The stuff on the wire looks like ordinary multiple species microorganism growth. Without a microscope, identifying this stuff is tricky
That’s what it looked like to me as well but the sliminess and clogged filters make me think it’s something else. Plus, I haven’t had any hair algae in this tank for months now.
 
OP
OP
R

RhiD08

Community Member
View Badges
Joined
Oct 28, 2020
Messages
80
Reaction score
45
Location
ontario
Rating - 0%
0   0   0
The slimy feel and white strings is indicative of a bacterial bloom. I don’t believe these blooms are normal in an established tank unless you are carbon dosing, exactly as you read. If I had to guess, flatworm exit impacted your biome and a bacterial strain is outcompeting and blooming.

If a bloom, ride it out for several days.
It’s so weird because I haven’t dosed anything or had any carbon inputs near the tank so it seems to have appeared out of nowhere. That’s my guess too, that the Red Sea Reef Energy AB+ and Salifert Flatworm eXit have messed with the balance in the tank. Should I perform a water change and clean as mush of it out as I can or let it go for a few more days? Any tips for the diatoms too?
 

Gone Reefin’

Active Member
View Badges
Joined
Mar 22, 2025
Messages
358
Reaction score
493
Location
Illinois
Rating - 0%
0   0   0
When I had a similar bloom, I did suck as much out as reasonable, and changed filters regularly as they would slime up. I would not worry about extra water changes. My tank was cycling though and did not have to worry about livestock impacts. Some extra flow or a bubbler may help in case excessive oxygen is being consumed.
 
OP
OP
R

RhiD08

Community Member
View Badges
Joined
Oct 28, 2020
Messages
80
Reaction score
45
Location
ontario
Rating - 0%
0   0   0
Regarding diatoms, would not worry. Actually a good sign as they may help compete with less desirables.
That’s good to know, I’ll just keep up with my regular water changes then and hope it passes soon. I was thinking about getting a conch for my sand bed so maybe I’ll look into that to help.

I’ve also been thinking and I may have figured out what’s causing the diatoms and bacteria bloom. Now that it’s summer, I’ve been out in the pool a lot and always use cream on my arms and hands after but I don’t always remember to wash my hands before putting them into the tank. So maybe the cream is acting as a carbon input and introducing extra nutrients? I’ll have to be more careful and remember to wash my hands and see if that helps.
 

TOP 10 Trending Threads

Back
Top