Tank break down/setup.

[Nick Barbier]

Hi fellow reefers,
I am about to break down my 125g mixed reef to replace the sand bed. The tank was originally setup in March of 2015, using six bags of Carib Sea Fiji Pink live sand and approximately 100 lbs of live rock. The live rock was transferred from my previous 75g mixed reef tank. I've had an outbreak of cyanobacteria off and on for about a year now. Tried using Red Slime Remover and then Reef Flux to get rid of the cyano. Both worked for a few weeks and then the cyano returned. I did several water changes but nothing seemed to get rid of this pest. This lead me to believe that the sand was saturated with nitrates. I tested the nitrate level with a Salifert Nitrate test kit and sure enough it was at 200! I'm surprised that anything is still alive in the aquarium. I am using a 25w Aqua UV sterilizer to kill the cyanobacteria in the water column, but it doesn't seem to have any effect. The other issue is that when I first setup the tank, I purchased what I was told was a zoanthid fraq. In reality, the frag was actually paly zoanthid. This highly toxic, invasive and dangerous species over time has taken over my tank. I've used pickling lime powder and later Aphasia-X. Both of these seem to kill most of the palies off for a short period of time but then they return with a vengeance!
I plan on replacing the old sand with 6 bags of Carib Sea Fiji Pink live sand. And I want to supplement the sand with Max Spec Bio balls in the 30g sump. I need to eradicate these paly zoanthids first, before I break down the tank. I am concerned that the toxins released by the palies along with the cyano might kill my fish and corals.
Is there a way to get rid of the cyanobacteria and the palyzoanthids safely without harming my tank inhabitants?

 

[Jason_MrFrags]

Ok to change your tank around, but I don't want you to think that swapping sand is going to be the magic cure for your cyano.
Sand isn't going to just hold/produce nitrates. Its going to come from the food you are adding to the tank. Try increase skimming to wet and more water changes, reduce lighting cycle. You mention using Red Slime Remover, typically that will get rid of it, but what did you change with your system/maintenance to keep it from coming back?

 

[Nick Barbier]

Ok to change your tank around, but I don't want you to think that swapping sand is going to be the magic cure for your cyano.
Sand isn't going to just hold/produce nitrates. Its going to come from the food you are adding to the tank. Try increase skimming to wet and more water changes, reduce lighting cycle. You mention using Red Slime Remover, typically that will get rid of it, but what did you change with your system/maintenance to keep it from coming back?

I always use my Octopuss 150SSS skimmer. When the outbreak first occurred, I reduced the photo period on my four AI 26s from 12 hours to 8 hours. I turned off all light spectrums except for blue and reduced that from 117% to just 50%. I have a Taam RIO 32HF return pump, an Icecap 1G gyre on the right side of the tank and a Icecap 2G gyre on the left side. I have 7 fish, and feed them one cube of Hikari Ocean Plankton, one cube of Hikari Spirulina Mysis shrimp and one cube of San Francisco Bay fish eggs per day. I only give them as much as they can consume in a few seconds and wait until the food is gone before I repeat. I do this until all three cubes have been consumed. This process only takes a few minutes. Afterwards, I give them one small sheet of Julian Sprungs seaweed. So, if anything, I under feed and not over feed my fish. I have a Blue Tang, a Yellow Tang, two Clarke Clowns, a Royal Grama, a Yellow Coris Wrasse, and a large Blue Damsel.
My water parameters are: Alk: 9, Ca: 420, Mg: 1300, NO3: 200, PO4: 1.01, SG: 1.026. I know that my parameters are out of balance.