How many bags of eco-complete for my tank?

You realize that within 6 - 9 mons. the two types of substrate will be mixed together, depending on how much pruning and moving of plants you do between now and then.
I've never seen anyone with a planted tank who could keep the layers separate over time.
As far as amount of material goes, I used 75lbs. in my 55s, but I like a deep substrate that slopes from 4 - 5" in the back, down to 1.5 - 2.5" in the front. I like lots of depth, especially in the back, for large and deep rooted plants.
Also, I feel that sloping the substrate adds the illusion of greater depth(front to back) that is lacking in a 55 by virtue of it's design.

Len

On the manufactures website they say one bag is equal to four bags of ordinary gravel.

Click to expand...

The bag mentioned this in reference to the CEC (cation exchange coefficient/capacity) and not actual tank requirement. What it basically means is that eco-complete is a porous gravel that provides alot of tiny nooks and cracks for roots to attach to and draw nutrients from, unlike most gravel with are basically polished rocks. You're still going to need at least 2-3 inches of substrate in mst areas for ease of planting.

I used 4 bags mixed with reagular play sand in my 150 gal tank. Before I had a little florite and onyx on the bottom with the sand. Since I've aded the eco my plants have been doing better.

Although I also added a Co2 system so that probably helped alot.

Trash

Try this...
http://www.plantedtank.net/substratecalculator.html

I feel so wrong posting another site here...

Trashman, did you just mix the eco in or lay it on top? I'm thinking of adding it to my Onyx sand (if...o.k., WHEN I redo my tank).