Y'know,
You could just use filter sand and add a cup of DE everytime you backwash, getting the same effect far cheaper. One 10lb box of DE is less than $10 and will last the entire season this way.

Poconos (one of the other moderators) and I both do this and have been VERY happy with the results. Since lately filter sand has been $5/50#, you would spend $30 on the sand, and then $10 on the DE. The filtering you get is much finer than sand alone.

Another trick to get a sand filter to perform better for me is running my pump at low speed. I have LONG noticed that low speed running (over longer times, of course) results in cleaner water. The lower pressure allows smaller stuff to get caught by the filter and not being pumped back into the pool.

I cannot remember, but I think Zeobrite reacts badly with some product--it may be Nature2, causing it to release ammonia. I'm personally NOT happy about mixing ammonia and chlorine in my pool. I assume it's dilute enough to be harmless, but when mixed they release a deadly gas.