Sand Substrate Observations

[presto]

I recently(2 weeks ago) set up a 10 gallon planted tank using sand.
I have never used sand in a tank before and I am noticing:

1) It turns black in spots
2) When I try to syphon it, it comes up in black clumps?
3) I am getting thousands of tiny white balls, few grains of sugar in size all over the bottom.
4) and it smells more than my gravel planted tanks, enough that my wife is complaining.

Right now I have some Vals, Hygro Diformis, and MTS snails and the other common kind on snail.

Looking for some understanding of why these things are happening and to eliminate the smell to make the wife happy.

Thanks.

[irene]

What type of sand are you using? Is it pool filter sand?  I recently set up a 5g and a 27g with pool filter sand and the 5g has sort of a swampy smell, the 27g has the black spots.  Have no idea what the black spots are.  I figured the swampy smell was due to in being new and maybe an ammonia spike or something, I haven't tested to confirm this though.

How long has the tank been set up for?

Irene

[Laura]

I've got PFS (pool filter sand) in with my piggy goldfish and haven't noticed any difference.
How thick a layer do you have?  Could plant roots or something be rotting underneath the substrate?

[CrazyFish]

http://www.cichlid-forum.com/articles/sand.php

I don't know why it would turn black but you need to stir it up occasionally to prevent it from going toxic(gas buildup).

[beowulf]

I had a tank a while ago with sand and plants and never noticed any of that.  I did have a lot of MTS in the sand so that might have helped....

[kennyman]

Sand can exclude O2 if it is too deep. The water diffuses through it slowly due to lack of pore space and this allows for microbes to pull the O2 out of the water as it passes by. Thus by the time the water reaches the lower levels by diffusion it has been striped of O2. At that point bacteria that are adapted to low O2 levels will propagate. These can consume Nitrate but they release gasses other than co2 during respiration. These are the gasses people warn about. If a large quantity is released in a sudden disturbance they can nuke your fish. These are the same bacteria that live in a septic system or the anaerobic muds of a swamp.

My brackish tank only uses 1/2 " of sand. this allows for little to no anaerobic activity. My planted tank is much deeper but the sand is mixed with organic material and soil. The high dencity of plant roots and burrowing snails help to keep anaerobic activity to a minimum.

[presto]

Thanks for all your responses.

I have done a 50% water change
Mixed pebbles into the sand (not visible from surface, hope to improve plant rooting)
pruned the plants
added some fertilizers
Added some swordtail fry
Added 4 endler/guppy pregnant females(for free if anyone wants them)

The Results (hindsight I should have done this one at a time so I know why it worked)
The white dots are gone
The black sand is only visible under the top layer from the side of the glass.
I will stir weekly to avoid toxic gas.
The plants seem to be doing ok

Too early to know for sure the problems are gone but a good sign at least.
thanks for everyone's suggestions.