Carbon dosing's effect on GFO

[Alex T.]

I've read Randy's article regarding GFO usage being unnecessary when carbon dosing, but could it actually be detrimental? Since GFO is so efficient at stripping PO4 from the water column, does the lack of available nutrients when coupled with carbon dosing create an abundance of bacterial clumping in sand and other problems?

I ask because I use to run both and would smell the vodka in the room with my tank for a few hours. After I stopped GFO and went strictly to carbon dosing I no longer smell the same dosage of vodka after it has circulated through the system.

Could the vodka have much less to "do" and thus cause bacterial problems if the GFO is kept online? Just making an observation. Since stopping GFO I upped my feeding and polyp extension/coloration in SPS corals has been noticeably improved.

[Randy Holmes-Farley]

I'm not sure what I wrote or your read, but some phosphate binder usage with carbon dosing is a fine plan. Carbon dosing can drop nitrate more than phosphate, leaving some phosphate unable to be reduced that way. :)

How much vodka were you dosing that you could smell it well after dosing? I dose vinegar and cannot smell it.

[Alex T.]

Woe Randy..that was fast!

At my peak before I reached 0 nitrates and phosphates on Salifert kits I was dosing 6 ml of vodka in a 150 display with @ 40 gallons sump volume.

I never really knew what phosphates truly were as I've come to learn that Salifert or any other liquid PO4 kits are unreliable. There always seems to be a little green algae on the rocks, but my sps seem fine and are growing and colorful.