How Deep

[Fishmanic]

How deep should I make the sand substrate in my new 29 gAL.   The most I would probably plant is some jungle val in the sand.  I may plant anubias and java fern on rocks or wood.

 

[Puffer_Nat]

It depends what you're planning to keep in there and things like if you plan on planting it I guess (although I nothing about planted tanks so sand might not even be suitable substrate)

 

[RaechalLee]

I would make it pretty deep, even deeper than you would want because when you clean it you will eventually start losing sand. I filled my 75 gallon with sand maybe 2 inches deep (I should have done 3 at least) because now it is like a year later and there are some parts of my tank where the sand is barely covering the bottom of the glass from all the cleaning and the fish moving it around. It is a pain in the butt to add more sand to an already planted an established tank haha so I would say more is better in this situation.

 

[RRaquariums]

When taking planted tanks into consideration sand is not what you want for most plants because it smothers the roots and has no beneficial property's but if your just doing some sand and then plants on rocks/wood I'd say about 3 inches that's what I put in mine and it works well.
As for cleaning in my cichlid tank which has 4 inches of sand in it I put a siphon tube in the tank and then move it down to the sand bed keep it about 2 inches off of the sand and any debris or fish waist will lift off the bottom and you can suck it up without losing lots of sand