Pointless to dose vodka if N/P already 0?

[dixiedog]

For whatever reasons, (low bioload, oversized skimmer, stingy feeding, etc) I've never had any measurable N or P. Couple times I've actually tried to build up a nitrate level (SPS are pale) but never got past about 0.5 before cyano showed up.

Is there any possible benefit for me in vodka and/or MB7? My understanding is NO, especially since my corals are already pale, and that I'd be better off continuing to try and increase the feedings.

Yes? No?

What about MB7 by itself?

[Randy Holmes-Farley]

Presumably you are doing substantial export now. Switching part of the load to bacterial consumption might reduce the cost/bother/etc of the methods you currently use.

In my case, for example, I greatly reduced the size and lighting intensity I used for macroalgae growth by adding vinegar dosing combined with some GFO. I had ~500 watts of lighting for the refugia, which I dropped to about 100.

[Fishbulb2]

Randy,

Could you elaborate real quickly on why you might use vinegar instead of vodka for carbon dosing? It seems like vinegar might effect pH more drastically than vodka.

Thanks,

FB

[Randy Holmes-Farley]

There is a bigger initial pH effect with vinegar, but less effect later. Eventually both are completely converted to CO2 with about the same pH lowering effect. I also add it very slowly.

I prefer vinegar because in my tank, vodka was more inclined to drive cyano growth. That may not happen in all tanks, depending on what species of cyano are present, etc.

[Fishbulb2]

Perfect, thanks!

FB

[tdwright1971]

Thanks Randy, Im going to try dosing vinager because My nitrates and phophates are both undetectable and I run gfo. been trying to dose vodka. My refugium cheato is dwindling. I have been battling cyano for months now. Would it be acceptable to inject the vinegar into the skimmer venturi? and what is a good starting point?

[Randy Holmes-Farley]

I'm reluctant to advise amounts on organic carbon dosing as it seems very highly variable and I've often dosed far more than other folks. In general, vinegar is about 8 fold more dilute than vodka, so if you are switching, try replacing one for the other over a week or two, using 8x more vinegar.

I dose it into the water coming from my display tank into two big rock filled refugia, trying to get bacteria to grow there. Into a skimmer may be OK, but I'd tend to worry about it impacting skimming or other issues. Some bacteira clearly grows on my GAC, which comes after my refugia.