I don't know if you meant the ats or the vodka. But the vodka is to consume the nitrates and phosphates by bacterial action not plant action. Which works in the display as will a refugium/ats. So therefore it should slow the macros just as vodka slows the algae in the display.

The ATS with it's high lights allows such things as cyano thrive on the screen. So if the tank becomes nitrates starved the cyano will thrive on the screen instead of the display. Hoperully, the corals and corraline algae will get first crack at the nutrients and then the ats picks up whatever is left over.

but all that is just my specualtion and what I have heard. Guys like you actually doing this is where I get my information. I just use a refugium and kill the display lights when cyano comes along.

my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden