#### beeky

##### Member

I worked out the amounts needed and the cost for a typical 91cm x 38cm aquarium (36" x 15") to give an average depth of 5cm. This volume works out to be ((91x38x5) / 1000), or 17.29l.

Interesting result.....

Flourite:

Guidelines say 1Kg is enough for 200cmsq to give a 5cm depth. Multiplying length x width of the tank gives a surface area of 3458cmsq, so 17.29kg would be needed for this tank. Each bag is 7kg, so that means we would need 3 bags (rounding up) at Â£26 each. Cost: Â£78

Eco-Complete:

A difference of opinion here on the number of bags. My calculations from their guidelines gives only 1.5 bags (i.e. 2) needed, but this didn't seem right to me. "The Planted Tank" website given in Aquaessentials description shows 3 bags needed which seems more reasonable, so that's what I've gone with. Each bag is 9Kg, so again 3 bags needed at Â£27 a bag, gives Â£81

Aquasoil:

This is nice and easy as they helpfully give the bag in volume rather than weight. A bag is 9l, so for our tank substrate volume of 17.29l, 2 bags are needed. Each bag is Â£28 giving a cost of Â£56.

So, there you have it. ADA Aquasoil is actually the cheapest option! Even if you can get away with using 2 bags of Eco-Complete, it's still no cheaper than AS.

I hope this helps people make a decision on their chosen substrate. I was quite surprised, and wish I'd worked this out before going for tropica substrate topped with black gravel.....

Graham