Depends on the input water, but usually between 0 and 1 or 2 at most. I know my input is very clean, about 50 tds, and my output is 0.
After my RO im usually around 2-4 TDS then DI strips that down to 0.
3 TDS water is definitely not the source of an algae bloom. You add far more pollutants than that just by feeding.
However, I don't see how your lighting alone can create the algae. There is an excess of nutrients in your tank feeding the bloom and the lighting may be facilitating that specific micro, as you said your spectrum appears to be in the yellow to red range.
Have you checked the water parameters? Especially those associated with your vegetation, silicates, nitrates, phosphates ect? How old are the bulbs? Have you burnt them in yet? What type are they (brand, spectrum and wattage)? Do you have macro algae to sap the nutrients away from the problem algae? Are there enough herbs in there to help you with normal algae control? Is temp too high, mid eighties?
Some quote I took from Wet Web Media regarding Lighting and algae.
Light and algae 10/7/03
"... do not cut back on lighting. Instead, focus on better nutrient export like getting the skimmer to produce quality skimmate 3-5 times weekly if not daily... and controlling feeding (thawing and discarding all pack juice
fom frozen foods... algae fuel!)"
"<Nuisance algae has little or nothing to do with quality light...(Saltwater-nut, perhaps your is not quality as you have stated) it is entirely about nutrient control. You have algae because you have nutrients under light... not because you have light. >"
This site has some great articles and FAQ's on Algae Control.