Okay, my complaint is: why didn't this show up as a new thread?!?! :irked:
Sealed 10 gallon kit. Do you mean the tank and stuff, still new in box? If so, I would read the expiration date on the water conditioner, if it's not past that, you can use it. I wouldn't use the food.
The filter should be absolutely fine, as the media should be sealed, and shouldn't be impacted by the length of time it's sealed. I'd still probably get a higher end filter such as AquaClear or Fluval (I use a Fluval C2 on my tank with my betta) simply because even though it's an additional $26 (or so, on Amazon) investment, the filters that come in kits tend to have disposable floss wrapped around charcoal for media, which is probably going to have a replace monthly instruction. Also, every time you toss the cartridge, you're tossing some of your biological filtration, as well. I've only had my C2 for 2 or 3 months, but I probably won't have to buy new media for a few years, as I don't run charcoal. If I feel a need to have something adsorb the biological stuff from the water to fix the smell or color, I'll buy a 100 ml Purigen pillow instead, for $10 or so, and that'll last years. My AC 70 has 250 ml of Purigen that I've had in there for 2 years, and I've regenerated it twice, and I probably have at least 2 or 3 more regenerations in there before I'll need to replace it.
The light bulb, I'm going to assume is a T8. Purple is an odd color, though. 8000k is heading toward the actinics, like you'd need for a saltwater tank, but it should still support some plant growth (corals apparently do photosynthesize). The bulbs are good for about a year of *use*, so just sitting in the box isn't going to impact the lifespan of the bulb. Current USA actually has a fixture that's LED, nifty (with all the little things you can do set it to do via remote control), on my shopping list (I want one for each of my 10s and my 55), and rates out as adequate for medium light plants. That said, they're about $90, I think, for the 24 inch long fixtures (right size for most 10s), and about $170 for 48 inch long fixtures, depending on where you get them.