Purple Cyanobacteria problem

Andre Duarte · Dec 16, 2019

Hi reefers.

I do have a 6 months 50 gallons tank that have developed a purple cyanobacteria in one corner a few months ago (possible the lowest water flow spot in the tank).
Now the cyano are growing much faster and I have to stop it.
I believe the problem is flow. For flow I have one Maxspect 330 Gyre pump on the surface that is blowing water at a max of 50%. It is set to 50% because I do have a very fine sand that goes everywhere if the flow is higher. I have Nature´s Ocean - BioActiv Live sand SamoaPink that is super fine. I don’t mind replace it if possible.

Solutions:
- Should I start syphoning out some of the bacteria and some sand with it, replacing the removed sand with new and dead one?
- Place the Gyre pump vertically in order to cover the four corners of the tank;
- My photoperiod is from 10AM to 5PM with a Kessil A360X. I have reduced the amount of power to less than half. Should I reduce even more? I do not have photosynthetic right now (corals or anemones).

I am facing from the start a Phosphate problem. I started with 1.45ppm (yes 1.45ppm measured with a Hanna Checker) that I have been slowly bringing back to 0.99ppm by using an Algae Reactor with Chaetomorpha.
Before having the Algae Reactor I was using Red Sea NOPOX with no success. I never had Nitrates so this could be the reason why it never worked. I have stopped NOPOX after installing the Algae Reactor.
I am tempted to start replacing the sand with new and larger one but I appreciate some help before that. Thank you all.

jgvergo · Dec 16, 2019

After more than a year of fighting cyano and algae, I finally tried ChemiClean. It worked wonders!

Soryu · Dec 16, 2019

Correctly identify the bacteria/algae with a test. Whether the peroxide test or a microscope, make sure you know what you're fighting before you start treating it.

Saltyreef · Dec 16, 2019

Thats feeding off excess phosphate. Keep syphoning and working on reducing phosphate with GFO but dont bottom it out shoot for .02ppm. Rinsing your sand and rocks prior to placing in the tank would have helped avoid a lot of it. Youll have to wait until it all leaches out. Sand may always give you issues. I fought this for years.....

Saltyreef · Dec 16, 2019

Ive also had great success using API E.M. to knock back cyano without any harm to reef inhabitants. Chemi clean worked eventually too. The EM was cheaper though

ReefsCubed · Dec 16, 2019

red slime or cyano is rarely a nutrient thing in terms of nitrates. Keep ticking that phosphate down, but careful keeping your nitrates at 0 for this can hurt corals in the future. Best thing to do in my opinion is just shoot for pristine water, and good consistent flow throughout the aquarium. Make sure your protein skimmer is tuned up properly and then any manual remove and cleaning of it will help it recede. In terms of the sand that is of course all choice however this may be a problem in the future with corals needing higher flow and the sand being too fine so keep that in mind as well, flow is one of the largest components to keep cyano back in my opinion. BRS has a great video on this topic on youtube: I recently just re-watched it myself, I am going through quite the cyano bloom myself haha. In the past this is what I did and it always sub sided. Good luck, hope this helps!
- Reefs Cubed

Andre Duarte · Dec 17, 2019

ReefsCubed said:
red slime or cyano is rarely a nutrient thing in terms of nitrates. Keep ticking that phosphate down, but careful keeping your nitrates at 0 for this can hurt corals in the future. Best thing to do in my opinion is just shoot for pristine water, and good consistent flow throughout the aquarium. Make sure your protein skimmer is tuned up properly and then any manual remove and cleaning of it will help it recede. In terms of the sand that is of course all choice however this may be a problem in the future with corals needing higher flow and the sand being too fine so keep that in mind as well, flow is one of the largest components to keep cyano back in my opinion. BRS has a great video on this topic on youtube: I recently just re-watched it myself, I am going through quite the cyano bloom myself haha. In the past this is what I did and it always sub sided. Good luck, hope this helps!
- Reefs Cubed

Thank you very much for your reply. I think I will start by trying to change the flow in order to reduce the cyano.
Regarding the sand, is it that bad that I slowly try to replace parts or the sand for a new one that don’t go everywhere?
I really think this is cyano, since I’m the morning the sand is clean.
In the future I will not get any corals, just anemones