Carbon Dosing observations

[Alex T.]

I have been carbon dosing for some time now (@18 months). At the beginning, the carbon source (vodka) was creating some incredibly foul thick skimmate as was to be expected. Recently however I started introducing MB7 as some cyano and other undesirables occasionally seem to creep into the system. I am on week 3 of the low nutrient dosage and have actually upped my feedings as well. Nitrates and Phosphates still measure 0 on my kits and the skimmer has been pulling less skimmate than normal.

is this to be expected? Could the new bacteria cultures from MB7 be outcompeting the skimmer for nutrients. Nothing is wrong with the skimmer and I figured that since I was feeding more I should see an appreciable difference in skimmate yet that has not happened.....a little confused.

Any thoughts?

 

[SDguy]

The whole idea with vodka dosing is that you grow bacteria, which take in the N and P, and then you skim it out. I suppose if the bacteria from the MB7 dosing is not in the water column, then it will be consuming the N and P, but not be skimmed out. The problem here is how are you actually then removing the N and P. Eventually, the bacteria that consumed it either has to be removed, or it gets consumed and utilized by other organisms, or it dies and releases the N and P back into the water.

 

[Alex T.]

I was thinking the same thing, but NO3 and PO4 are still measuring the same.

Don't get me wrong....I still pull skimmate....but nothing like before. My guess is that maybe the SPS corals may be taking up more bacteria as food which would otherwise have been skimmed out.

I almost feel like feeding the fish until I measure some nitrate.

 

[SDguy]

Well, you state "kits"... IMO you can't measure phosphates with a kit, so not sure you'd be able to tell anything in the ranges we are looking at.

You probably just are "maintaining" now, so you get less skimmate.

 

[Alex T.]

Sorry....NO3 kit is a Salifert checked against a friend's Salifert kit with the same results.

PO4 kit was a Salifert. I know it's pretty useless so I checked against a friend's Hanna Checker and it was .02

I really don't measure phosphate. IMO unless I see a visible sign of increased algae growth, less polyp extension or decreased growth and browning of corals I don't test for it.

 

[SDguy]

I'm the same way