Handling cyanobacteria in a macro tank

[Newms118]

So I have macro algaes in both the DT and refugium, and I cant seem to keep cyanobacteria away. My macros in the DT dont grow that well and tend to get tons of detritus on them. However, in the refugium, its getting swarmed by cyanobacteria like every week and a half, some im constantly having to use chemiclean. I clean the algae and they do grow a bit in the refugium, but how do you guys keep cyano from coming, especially when the nitrate is above 5 ppm and phosphate at about 0.3 to 0.5? Its a losing battle for me all the time since when the cyano grows, its attaches to my plants and ends up killing them a bit. Do you have any pumps in the refugium to help blow the plants around bc its pretty calm water down there and I dont know if its just too calm.

[Subsea]

Even in mature reef tanks, cynobacteria is alive and well. Even when phosphate is undetectable in water column, cynobacteria can convert inorganic phosphate in calcium phosphate substrate into organic phosphate using a biofeedback loop as discribed by Randy Holmes Farley. Cynobacteria is the “nitrogen pump” for planet earth my converting free nitrogen gas into ammonia.

With your situation, you must remove cynobacteria with siphon and vacume. Encourage your desirable macro by frequent pruning to encourage growth. Both macro pruning and cyno vacuuming will export nutrients.

Why is there so much detritus? While I have used chemi clean, I will not use it again.
Did you have much detritus before introduction of chemicals?

[Michael Hoaster]

Increasing current can help with cyano. It sounds like it has become chemiclean resistant now, in your tank. Try a thorough manual removal, then a four day black out. Keep favoring your macros as best you can. Eventually you'll win. I had cyano for three months before finally conquering it. It was hell.

[Newms118]

Originally Posted by Subsea

Even in mature reef tanks, cynobacteria is alive and well. Even when phosphate is undetectable in water column, cynobacteria can convert inorganic phosphate in calcium phosphate substrate into organic phosphate using a biofeedback loop as discribed by Randy Holmes Farley. Cynobacteria is the “nitrogen pump” for planet earth my converting free nitrogen gas into ammonia.

With your situation, you must remove cynobacteria with siphon and vacume. Encourage your desirable macro by frequent pruning to encourage growth. Both macro pruning and cyno vacuuming will export nutrients.

Why is there so much detritus? While I have used chemi clean, I will not use it again.
Did you have much detritus before introduction of chemicals?

So I've started vacuuming my sand bed as best I can, but I cant reach all of it due to rock work. Most of the sand thats exposed does get vacuumed. I dont feed heavy by all means, and I've lost several fish recently so the amount of food needing to be fed has been minimal. I do supplement nitrate and phosphate but my levels only get between 4 - 8 ppm nitrate and 0.1 - 0.5 ppm phosphate. The detritus just tends to build up on the macros, especially in the DT, despite having my MP40 and MP10 pumps going pretty good. Ive added a lot of carbon to try and pull out organics with additional skimming and thats only helped minimally.


Heres what I think is happening. My macros in the refugium grow well under a new LED grow bulb. I then take the extras thats have been getting bigger and putting them in the top DT. My LEDs on the top DT have become bad (I think) so the LEDs just dont produce enough of the right kind of light and the plants grow/wither slowly. I have gracilaria hayi, bryothamnion, codium, gracilaria, Cymopolia barbata, red grape, and galaxaura in the DT. None seem to grow well. The bryothmion is at the bottom of the tank near high flow areas, and I cant tell its grown at all, it just get algae all over it so Im constantly having to scrub it (huge huge pain). The barbata kind of grows off and on. The red grape had all the grapes drop off and now is just started to produce more (its at the bottom too). The Hayi and galaxaura where higher up in high flow areas, same thing for them. So as the DT plants dont do well, the excess nutrients causes cyano to flourish in the refugium (it grows really close to the grow light). Eventually it starts growing on the refugium plants, they get choked off, die and add more nutrients. I then do the chemiclean and kill off the cyano and repeat for a week.


I try removing the cyano in the refugium, I wipe it off the walls etc. It just starts growing on all the plants, and I cant vaccum it off. It seems doing a freshwater dip of the plants will kill it bc the bacteria is so sticky.

[Newms118]

Originally Posted by Michael Hoaster

Increasing current can help with cyano. It sounds like it has become chemiclean resistant now, in your tank. Try a thorough manual removal, then a four day black out. Keep favoring your macros as best you can. Eventually you'll win. I had cyano for three months before finally conquering it. It was hell.

The refugium section is pretty low flow, I can try adding a powerhead but I need to find a tiny one bc I dont want the plants getting blown all over the place since the size of the refugium is small.

[Subsea]

Originally Posted by Newms118

So I've started vacuuming my sand bed as best I can, but I cant reach all of it due to rock work. Most of the sand thats exposed does get vacuumed. I dont feed heavy by all means, and I've lost several fish recently so the amount of food needing to be fed has been minimal. I do supplement nitrate and phosphate but my levels only get between 4 - 8 ppm nitrate and 0.1 - 0.5 ppm phosphate. The detritus just tends to build up on the macros, especially in the DT, despite having my MP40 and MP10 pumps going pretty good. Ive added a lot of carbon to try and pull out organics with additional skimming and thats only helped minimally.


Heres what I think is happening. My macros in the refugium grow well under a new LED grow bulb. I then take the extras thats have been getting bigger and putting them in the top DT. My LEDs on the top DT have become bad (I think) so the LEDs just dont produce enough of the right kind of light and the plants grow/wither slowly. I have gracilaria hayi, bryothamnion, codium, gracilaria, Cymopolia barbata, red grape, and galaxaura in the DT. None seem to grow well. The bryothmion is at the bottom of the tank near high flow areas, and I cant tell its grown at all, it just get algae all over it so Im constantly having to scrub it (huge huge pain). The barbata kind of grows off and on. The red grape had all the grapes drop off and now is just started to produce more (its at the bottom too). The Hayi and galaxaura where higher up in high flow areas, same thing for them. So as the DT plants dont do well, the excess nutrients causes cyano to flourish in the refugium (it grows really close to the grow light). Eventually it starts growing on the refugium plants, they get choked off, die and add more nutrients. I then do the chemiclean and kill off the cyano and repeat for a week.


I try removing the cyano in the refugium, I wipe it off the walls etc. It just starts growing on all the plants, and I cant vaccum it off. It seems doing a freshwater dip of the plants will kill it bc the bacteria is so sticky.

When you say “bacteria is so sticky” I have difficulty equating “so sticky” to cynobacteria. Yes, cyno will blanket anything but in my experiences it has always been easily siphoned or blown away.

[Flybynight]

Anytime you change light source suddenly you run the risk of throwing things into shock.

[Newms118]

Originally Posted by Subsea

When you say “bacteria is so sticky” I have difficulty equating “so sticky” to cynobacteria. Yes, cyno will blanket anything but in my experiences it has always been easily siphoned or blown away.

If its not cyanobacteria I dont know what it is. Since ill get it in a week again, Ill take some pics so you can see how it grows on the plants. I mean sticky in the sense that I can brush the plant with a pipette tip and it wont completely clean it off. It forms such a thick mat that its more of like a skin. So I can pull it off a little bit but that wont get it all.

[Newms118]

Originally Posted by Flybynight

Anytime you change light source suddenly you run the risk of throwing things into shock.

I understand that, its just been months at this point, so I would think they adapted by now. And they didnt take nearly this long to adapt to the grow light.


Last night, I was even looking to see if I could supplement the light by adding an LED fixture on tip meant for planted freshwater. Something cheap though, like 40 bucks.

Like this: https://www.marinedepot.com/Current_...LTFILD-vi.html