thickness of the substrate/fertilizer layer?

[roy]

folks,

i recently set up a 3.5 feet planted tank and have got almost 10kg worth of sand leftover. i'm thinking whether to give/sell the sand or top up more sand into the tank.

presently, the sand and fertilizer layer is about 4" thick. is this sufficient or i should go for 5" thickness.

appreciate all your help.

cheers,
roy

[DEA]

how far is the surface of the substrate from the fert? ie, you covered the fert with how much gravel?

[roy]

thanks dea!

can't provide the info now cos now in sg. do the measurements when i get back and post again.

cheers,
roy

[DEA]

the important thing ime is how far the fert is from the surface
if it's too deep, the plants don't really get the benefit of the fert
about 1.5 in of gravel on top of the fert should do