Quick question: Laterite vs Flourite?

[Jhereg10]

I'm about to set up my substrate, and from various articles I've read I see that my plants will be helped by adding a lower substrate of some material.

On the Skeptical Aquarist

http://www.skepticalaquarist.com/docs/substrate/laterites.shtml

I read that laterite and flourite can be blended and used together. The author also mentioned cat litter (hypoallergenic versions so they won't have perfume additives or clumping agents) but noted this was a bit risky. (I hear they can also have aluminum compounds sometimes, which is also a bit of risk).

My lfs says they do not stock laterite, but can order it and have it for me tomorrow (said $30 per bag and I would probably need 2 bags...sounds steep. Dr. Foster Smith.com says 75 grams of lateriate would be enough for a 75 gallon aquarium (that would run me about $22 total from them plus shipping, though express shipping would probably bump that up to $40, so the lfs may not be far off by comparison).

Thoughts?

[Skittyfish]

I already had my tank set up and I used two boxes of Pure Laterite and mixed it into my gravel. It was a huge mess.
If I was starting a new tank I would probably spend the money and order Flourite. But this is of course just my opinion.

[Jhereg10]

Ended up buying "Aquatic Potting Soil" (Schultz/Profile) which is similar to laterite (firm, reddish clay chunks) instead of actual laterite/flourite. Got it at my local Lowes.

Bottom layer is 50% APS, 25% gravel (1-2mm), and 25% sand. Upper layer is almost all gravel.