Your tank has been setup since the beginning of this month, and in your previous post, you mentioned you have not detected any ammonia, nitrite, and nitrate? That's odd, indeed, especially you mentioned you used turkey baster to blow off some smelly black dead stuff. I reckon your test kits are not doing its job right.
What is the brand name of the kits you are using? Is there a date printed on the box?
There are nutrient in the tank. Mostly coming from die-offs in the LR. Cutting down on the light will help, but once you turn on the light in the future, diatom will sure follow. How bad is the diatom coverage? The ones on the glass, go ahead and scrape them off with razor blade (becareful if you are using acrylic tanks). Since this is the 3rd week into the cycle, why don't you do a 25% water change as well right after the scraping. And while you are doing it, take the LR out and blast them with a powerhead to remove any dead matters and put them back in afterwards. Discard the rinse water.
Which skimmer did you end up getting? Is it picking up the skimmates?