Nitrites won't go down!

Hey all.

Well. Been doing 25% water changes on my tank daily. I use only R/O water. So it's been getting expensive. For tank spec's, please see my tank spec's below.

I only have live rock in there right now, besides a single snail that is either a Turbo or Astrea.

On the bright side, my ammonia level has dropped to between 0.25-0.50ppm, but on the down side my nitrites are still through the roof at over 5ppm.

I'm worried this will be very bad for whatever may have survived to this point on my rock. From everything I've searched on this site, the only solution to high nitrites seems to be water changes. They don't seem to make a dent in the level of nitrites, however.

:argh

Sorry, just getting frustrated. Please, is there anything else that may help in reducing the nitrites? Thanks in advance.

That's true...

I think I'll try taking a sample to Petco, as much as I dislike the place, just to see what they're instant tests show. I don't think my LFS will do a test for me, but who knows, since I'm in there a lot. I will try there, but they have a big sign at the front stating that they absolutely will no longer do water tests for customers.

If the readings come back high from these places as well, what should I do? If the water changes aren't lowering the level to under 1ppm, do I have to worry that everything will be killed off?

Thanks again.

Thanks all for the responses...
Jason, I don't want to name names, but I can PM you the name of the place if you want, you may know it. They have two stores, one in Ventura, and one in T.O.
Dave, yes I am skimming, full-time 24/7. I'm emptying about a full cup every day or so.
LT1, what's Calupra, if I may ask?

Haven't had time to get those tests yet from any store, but will do so probably tonight, along with retesting myself to see where they're at. Thanks again all.