You have a few problems.
1. Your pc lighting set up is probably not intense enough to get the light the anemone needs to the bottom of your 24" tank. Even if you had 4x96 watt pc bulbs, it would be iffy. You really need a couple 250 watt metal halides.
2. I don't want to rush to judgement, but since you have a FOWLR and a wet/dry filter, I'm guessing that your nitrates are likely too high to keep an anemone for long. Anything more than 5 ppm is pushing it with an anemone.
3. Haddoni (saddle) carpets have a pretty powerful sting when they are healthy. It is very likely that any medium sized tangs, dwarf angels, small wrasses, and gobies in your tank will soon be anemone food.
IMHO, it would be a good idea to take the anemone back and see if you can get store credit for it.