3-days Lights out to combat Cyano

So I've been dealing with cyano for a little over a month now. It's not as bad as I've seen in other tanks but it is annoying and ugly. I've tried a number of things to correct it including; increasing flow, reducing the amount I feed, running chemi-pure elite (I have considered just running carbon and GFO, but have not done it yet), more regular water changes, syphoning it out by hand, etc...

Tank and water parameters are all inline and full history of them can be viewed on my Aquatic Log profile (click the image below). They've been relatively stable for some time now.


I also should note, back in November, I had a Nitrates shoot up to 40ppm (I was over feeding). since then, I have gotten it under control and the cyano did not begin to emerge until way AFTER I got my nitrates down below 5ppm, which was around early Januarary. Also My phosphates have always been (and still are) either undetectable or very very low.

So - that brings me to me next attempt to deal with this and my questions. I've started a 3-days lights out to try and starve the cyano.

1 - Are there any signs I should watch for in some of the stony corals that would warrant me turning the lights back one - or will they be OK for three days.

2 - I have an DYI algae scrubber in the Fuge sump - should I clean it and take it offline for the three days, or just leave it in place?

3 - I have auto dosers for Alk and Cal - should these continue to run as normal, or should I take those offline as well? My thinking is the corals and coralline will grow less during the 3 days with now light, so they may not need it.

4 - When the 3 days are over, should the lighting schedule/intensity go right back to where it was, or should I ease the tank back into the regular schedule and intensity?

5 - Are they any other things I should keep in minds and watch for during these three days?

Thanks in advance for any help or in site you can provide

 

Well will be interesting to see what the guru's have to say..

1) I would say give the GFO a try. I see you are only registering a .01 Phos but worth a shot
2) have you tested your RO water?
3) After you mixed up your water for the water change have you tested that prior to doing the water change?

 

1 - Do you think I should try the GFO as opposed tot he lights out, or once the lights out is done?

2 - I have not, and I probably should. Right now I'm getting it from my LFS, and I've been pretty consistent on getting it from the same store each time. Should I test it for both phosphates as well as nitrates or something else?

3 - For the water changes, I always used Catalina water. I have not tested the water every time, but the 2-3 times I have tested it in the past, it's always been spot on. Unfortunately, I don't have those exact numbers. The next water change, I'll be sure to test t and record the numbers.

 

Personally I would go the GFO route first..

Since you are having an issue yes I would test phos and nitrate on the RO water. Also investing in an ro/di unit is well worth it.. pays for itself pretty quickly.

Have heard of Catalina but never used it but again worth a check.

I am sure there will be much more knowledgeable people to chime in.

 

You have a 120 gal tank and don't have an RODI unit!?

How many gal water changes do you do and how often?

 

Would you do just GFO, or GFO and Carbon? I have a small Two-little fishes Phosban reactor that's not currently in use, so I could set it up pretty quickly, but I could only do one without the other until I could get another reactor in a week or so.

The Catalina water is NSW (natural sea water). I've always had good luck with it both with this tank and my previous 50 gallon. This cyano outbreak is the first time I've had to deal with it since I got into this hobby 2.5 years ago. So I'm still a bit wet behind the ears so to speak .

I generally do a 20-25 gallon change once a month with a few 5-8 gallon changes mixed in ever few weeks or so. I also go through about 6.5 gallons of top-off water ever 3-4 days. Definitely expensive which is why an RO/DI unit is in my future.

 

I'd set up the GFO. Don't worry about carbon, it's not very important.

I'd think you'd want to be at 40gal per month on a 120 with a light feeding schedule.
But every tanks bio load is different.

Also, what type of lights are you using?
How old are the bulbs and what spectrum?

 

Yup agree on doing the GFO, and good question on the lights.

 

the 40g a month would only be possible once I get the RO/DI and start mixing my own water - but I would have to imaging it would make quite a difference.

The lights are two 160w 16000K Maxspect razors. They where bought used so I don't have a full history on the lights. I did a full PAR survey of the lights a while back, and the only change I've made since is I've raised the lights - they are now 14in off the surface of the water get better spread. You can see that survey and the lighting program from this link.
Par Measurements | OnlyTono

 

A suggestion on the water change issue: I've been using distilled from Walmart. Costs about $1/gal. You could be changing 10 percent/week pretty quickly. I'd start with water changes. With that much light the cyano is going to want to grow.