My war with Cyano, check my battle techniques?

I've been battling cyano ever since I aquired the tank (90 gal w/25 gal sump/fuge). It started with bad LR, which had PO4 deposits in it, bringing the PO4 levels to >2-5ppm, even with the use of GFO and liquid precipitates. That LR was swapped out a month ago.

Params right now (and have been for a month): amm, nitrite, nitrate, and phos all 0, dKH 8, calc 450, ph 8.3. Lighting is a new 6 bulb T5 fixture, all bulbs are 3 months old. Bioload: 1 small each yellow and hippo tang, 1 percula, 1 firefish, 2 chromis, 1 sixline, 1 yellow watchman, CUC, skunk shrimp, few assorted corals.

What I've done:
-Increased flow in DT to 43x turnover.
-Replaced all LR/sand with new rock/sand, tank now at 0 PO4
-Feed 2"x1" piece of algea for the tangs and either 1/3 cube frozen or 2-3 pinches of food per day, all consumed in less than 1 mintue... corals get 1 feeding per week.
-Added fuge (about 8 gal) with DSB, chaeto, mangroves (26 watts CFL for 14 hours, 10x turnover)
-upgraded skimmer to reef octopus 110
-10% weekly WC
-syphon cyano from LR/sand bed weekly
-running 1/2-1 cup GFO

It's not as bad since I replaced the LR, but still getting a decent amount of unsightly stuff hanging off the rocks and sandbed. The worst is in the fuge, it's like a swamp in there, choking out the chaeto. I'm wondering if using the sand I started with (I started with new sand when I set up the tank, and then tossed most of it when I changed out the rock, except for the DSB in the fuge) is possibly leaching PO4?

I'm thinking my next step is to turn off the fuge light for a week and see what happens. That's where it's the worst. I've got some Chemi-clean in my cabinet that's starting to look tempting, but I'm really trying to hold off on using it. I feel like I'm winning, just cant seem to kick it.

Input, ideas, or feedback?

 

get in there and physically remove as much as you can. pull it out by hand however you can. get it clean. keep light off for 2 days. water change after blasting your rocks, try to catch water floating pieces. change out filter sock. lights out for two days. repeat if needed. good luck.

 

im dealing with the same issue and just finihed what i listed...

 

Sorry to hear. I love your analogy “…the fuge, its like a swamp” – a fuge is a swamp. I would suggest you leave it be, what survives in the refugium is the strongest absorber to your tanks specific excess nutrients.

As for the tank, I am not a fan of disturbing sand or anything in a refugium. Please test the water pre fuge and post fuge to see of there is an increase in PO4’s – this will help you identify if the sand you used was the incorrect product and is leaching phosphates. Don’t kill the lights in the refugium, your refugium is doing what it should be doing. Perhaps increase your DT flow so that the cyano is limited when it comes to attaching.

You say that it feels like you are winning, and your posts reads as if you are – so if it walks like a duck and farts like a duck and all that…..

Use the chemi-clean, it’s a great product ! pick up the elite and use it. I would suggest chemi-clean elite, purigen and rowaphos – the trilogy of battle gear. Good luck!

 

+1 on Crimson ghost. Also, you didn't mention carbon. This is very important as it can remove organics. Siphoning is also important. And you may want to run GFO. If you have cyano growing, there has to be a supply of phosphate.

 

Sorry, forgot to mention I've started running carbon with the GFO.

I'm not disconnecting the fuge, just turning the lights out for a few days. My guess is that the chaeto and mangroves will survive, but hopefully the cyano that is essentially "suffocating" them will not. If that works, I might do a complete system lights-out period.

 

I still strongly urge against messing with the refugium. Of course there are many ways of going about things, good luck.

 

For various reason, it is likely beneficial to have some cyano in your fuge. Or at worst, not detrimental. I know people have cyanophobia and want to get rid of it all, but killing it by turning off the lights, will just release lots of organics and possibly toxins into your system. I'm a fan of limiting growth and siphoning if you feel you must get rid of it.

 

I completely agree. Turning off your fuge lights would be a huge mistake. You are better off having the excess nutrients being absorbed by the cyano in the fuge, rather than the cyano in the display tank. If you think you have some unsightly cyano in your DT now, turning off the fuge lights will just magnify the problem (in your DT).

 

I know this sounds wierd, but after turning off the lights for 4 days, my chaeto doubled in size during the lights out period, and the cyano has disappeared from my DT. Now that the lights are back on, the cyano has grown back in the fuge, but I'm okay with that as long as it stays there. I'm sure there's other things in play as well, such as replacing the GFO/carbon, but the lights out didnt seem to hurt anything at the least.