Cyanobacteria in 1.5 year old tank

Tammy J · May 10, 2023

Hello,
I am seeking help. My tank is a year and a half old but I am still struggling with Cyanobacteria. I have a fish only tank (7 fish total in a 55 gallon tank). My water levels are normal, I have a several snails and crabs for clean up and I try my best to not over feed. I’m not sure why this is still happening. I have cut down my live sand by half and I vacuum the sand and scrub the rocks twice a month, if not four times. After I vacuum, the Cyanobacteria comes back full force within two days. Does anyone have any advice? I’m not sure what else to do.

The_Paradox · May 10, 2023

What’s your flow look like. Also before everyone else asks, what’s your nutrient levels… not that I think it matters that much.

FrugalReefer · May 10, 2023

I had cyano in my tank at about the 20 month mark. I concentrated on things like decreasing my nutrient import (feeding), increasing my nutrient export (GFO, etc), and syphoning the cyano whenever I did water changes. It’s all about slowly making adjustments to how you import/export nutrients, seeing the results over time to see if it’s helping, and then slowly making more adjustments if the cyano isn’t disappearing. This along with siphoning the stuff out. The cyano in my tank eventually got to the point of just a very few small patches here and there, which for me, is a win. This is why I have never used and don’t believe in quick fixes like chemiclean. It’s just a band aid and isn’t attacking the root cause.

blecki · May 10, 2023

IME you can't starve Cyano without first starving everything else. Not sure you can actually eradicate it without a chemical solution. If you have nutrient export through chaeto or another macro, I say just nuke it with chemiclean and be done with it.

Stephen Glover · May 10, 2023

your nutrients are probably out of balance. What is your nitrate and phosphate levels?

bushdoc · May 10, 2023

I second checking nutrient levels. I have a feeling , you could add more rock and I would recommend some Live Rock to increase biodiversity.

The_Paradox · May 10, 2023

I've seen cyno in ULNS tanks and I’ve seen it in tanks with phosphate over 8ppm. The only commonality I have noticed is low flow or screwed up lighting.

fish farmer · May 10, 2023

The_Paradox said:
I've seen cyno in ULNS tanks and I’ve seen it in tanks with phosphate over 8ppm. The only commonality I have noticed is low flow or screwed up lighting.

I had a tiny patch of cyano for several years under a ledge. My tank was doing great, zeros on nutrients, but if my flow was off, it would pop up on my sandbed. Currently my flow is a little off in spots and I did some rescaping recently and up popped the cyano again.

To the OP, I would increase flow in the areas and increase removal of detritus in those areas.

Also what do you use for skimmer/filtration. From the picture your tank looks a little green, I'm thinking you may need more export of waste.

fishyjoes · May 10, 2023

Tammy J said:
I have cut down my live sand by half

How long ago did you remove half the sand?
I've seen reports of tanks being unstable for several months after removing substrate (there's BRS videos on youtube about when they removed sand from one of their long running tanks and it became a nightmare for a while)

Mr.OK · May 10, 2023

I had the same issue but it was covered on some rocks, my numbers were nitrates. 8.3, alk 9.3, phosphate 0.03, calc, 450, mag 1120, I used chemiclean and with 48 hours it was all gone. But i am newbie,

nuxx · May 10, 2023

I got it too around 1.5 years, heavy feeding though.

Tammy J · May 10, 2023

The_Paradox said:
What’s your flow look like. Also before everyone else asks, what’s your nutrient levels… not that I think it matters that much.

I don’t have my nutrient levels at this time but will check. Flow may be an issue…I have 2 power heads but am not sure the best way to position them.

Tammy J · May 10, 2023

FilAmReefer570357 said:
I had cyano in my tank at about the 20 month mark. I concentrated on things like decreasing my nutrient import (feeding), increasing my nutrient export (GFO, etc), and syphoning the cyano whenever I did water changes. It’s all about slowly making adjustments to how you import/export nutrients, seeing the results over time to see if it’s helping, and then slowly making more adjustments if the cyano isn’t disappearing. This along with siphoning the stuff out. The cyano in my tank eventually got to the point of just a very few small patches here and there, which for me, is a win. This is why I have never used and don’t believe in quick fixes like chemiclean. It’s just a band aid and isn’t attacking the root cause.

Ok, so how do I increase nutrient export? Is this with a skimmer?

Tammy J · May 10, 2023

Stephen Glover said:
your nutrients are probably out of balance. What is your nitrate and phosphate levels?

Last time I checked, Nitrate levels were 0. I will need to check both again and will get back with everyone.

Tammy J · May 10, 2023

bushdoc said:
I second checking nutrient levels. I have a feeling , you could add more rock and I would recommend some Live Rock to increase biodiversity.

I have 5 live rocks as it is and 2 that were not live when I started my tank. Do you still recommend more? I wasn't able to get a picture of my entire tank in on this photo.

Tammy J · May 10, 2023

fish farmer said:
I had a tiny patch of cyano for several years under a ledge. My tank was doing great, zeros on nutrients, but if my flow was off, it would pop up on my sandbed. Currently my flow is a little off in spots and I did some rescaping recently and up popped the cyano again.

To the OP, I would increase flow in the areas and increase removal of detritus in those areas.

Also what do you use for skimmer/filtration. From the picture your tank looks a little green, I'm thinking you may need more export of waste.

What do you recommend for a 55 gallon tank? A protein skimmer? Something different?

Tammy J · May 10, 2023

fishyjoes said:
How long ago did you remove half the sand?
I've seen reports of tanks being unstable for several months after removing substrate (there's BRS videos on youtube about when they removed sand from one of their long running tanks and it became a nightmare for a while)

I removed the sand around the first of the year...maybe February at the latest. I had 4 inches of sand and decreased it to two inches. (It isn't even in my photo because my clown fish like to sweep the sand in piles.) I will check in to those videos, especially if they have advice on how to fix this! It is annoying!

Dweezilz · May 10, 2023

I've been told many times in my fight with dinos by a very experienced group of folks that the balance between NO3 and PO4 is critical with Cyano and you want 100x ratio. If PO4 is .08 you want NO3 to be within 20% of that or close to 8, etc. Also getting an ICP water analysis can reveal some other imbalances that can have an effect on cyano. I'm about to learn what those things are myself. It's felt with the correct ratios and levels and some manual removal cyano will burn itself out. Chemclean works but doesn't fix underlying issues that can inevitably allow cyano to come back.

Stephen Glover · May 10, 2023

Tammy J said:
Last time I checked, Nitrate levels were 0. I will need to check both again and will get back with everyone.

0 nitrates are definitely part of the problem. What is your nutrient export regime?

FrugalReefer · May 10, 2023

Tammy J said:
Ok, so how do I increase nutrient export? Is this with a skimmer?

Use more GFO or replace more often, use more activated carbon or replace more often, clean or replace filter socks more often, do bigger water changes or do more often, add a refugium with macro algae if you don’t have one, get a bigger skimmer. I’m sure there’s more but these are what come to my mind. Oh, add more corals since corals use nutrients also.