Carbon Dosing Help

[Emmanuel75]

System: 75 DT, 40 Sump/fuge (culerpra, cheato 24/7 lighting), H&S 150-2001 Skimmer, 2 BRS reactors (HC-GFO, ROX), Dual 14K Pheonix 150 MH bulbs changed sept, 3 Panorama led modules atinics, 2 MP40.
Bioload: rabbitfish, 2 clownfish, kole tang, pseudochromis

Stats: Nitrates: 10, Phosphates 0, Ca: 500, KH: 11.
Dosing: Kalk (ATO), 20mL Vinegar
Water Changes: Salt Mix: Red Sea Coral Pro - 5gal 2/wk

I started carbon dosing many months ago using vodka at first, over about 1 month I got my Nitrates to remain undetectable using red sea test kit. As directed, I cut my dosage in half to about 5mL per day. While on vacation in august a sitter overdosed and overfed which began my battle with Cyano. I backed off on dosing once I returned while performing WC to no success to eliminate the problem. After reading about other experiences on RC, I switched to vinegar in place of vodka. Still no change. I had added a couple SPS pieces over time, which have been doing fine so I didn't sweat the little bit of Cyano growing. But it has gotten worse. I now have to black out 3 days once a month to keep it in check. Lately I have been keeping my Phosphates around .03 or lower, but I know as long as Cyano is growing I may get false negatives. I change out GFO & ROX every 2 weeks, sometimes sooner if I notice HA growth. Over the last few months I've tried vinegar, and a mixture of both vodka and vinegar to no success.

My concern is that the blackouts are causing a raise in Nitrates, which is in turn upsetting my SPS. I've lost two pieces over the last month, and getting upset. I even got to a point where I was doing 5 gal WC 5 days per week, and still no change. I've avoided big changes to avoid shocking the system, but I'm running out of options. The skimmer was changed around march and has been doing great. I did have a reef devil before, but I never could get it to run right for me. I get about a full cup worth of nasty black skimmate every 3-4 days.

Last April during the blackout, I stopped dosing and that was probably the cleanest I have seen my tank since I before the Cyano began. But was very hard to get Nitrates back down. I just completed another blackout, Nitrates are at 10, but I kept dosing vinegar during the blackout this time, but It didn't quite clean up all of it this time. Sorry for the long email, I'd figure more info would be better for advising on how to fix this. Any suggestions would be appreciated.

[Emmanuel75]

I didn't talk about feeding, but again to reduce phosphates, I have drastically reduced feeds to 1 every 3 days. Either krill, or mysis, once in a blue moon vegi flake food or nori.

[kissman]

someone suggested to me that I should double my amount of GFO or change it out every week. I doubled my amount from 1 cup to 2 cups on my 55 and that has helped. I too am dosing vinegar

[Emmanuel75]

Originally Posted by kissman

someone suggested to me that I should double my amount of GFO or change it out every week. I doubled my amount from 1 cup to 2 cups on my 55 and that has helped. I too am dosing vinegar

Thanks for the reply. I think the recommended dosage for my water volume for HC-GFO was a little under 1 cup. I'm currently using 2 cups worth when replacing. I changed GFO on 5/12 when I started the blackout, I was going to wait till next week to change again.

[Randy Holmes-Farley]

I generally wouldn't recommend organic carbon dosing as a way to deal with cyano. But using GFO is a good way to go.

If you read 0.03 ppm phosphate with an ongoing cyano problem, I'd use more GFO or change it more frequently. I'd also manually remove as much cyano as possible by siphon.