sand bottom, how deep???

[Magnum Man]

my cupid male is digging again, probably a feudal attempt, being in a densely populated community tank... I like my sand about an inch deep, but I'm not really trying to breed right now, but is it better, if he has a smooth surface on the bottom of his nest ( like the tank bottom ) or is it better for making a nest, if he gets as deep as he wants, with sand still on the bottom??? ( just thinking about any future breeding tanks )...

in my barb tank , the sand is pretty even, at an inch, but in the cichlid tank, with various diggings, it ranges from 1/4 inch, to 2 1/2 inches deep, where they pile it up...

 

[TwoTankAmin]

As a rule of thumb if a tank has no live plants which root in the substrate, by 1 inch deep the sand is anaerobic. The nitrifying bacteria are closer to the surface as they need oxygen.

What is really interesting is for plants which have roots in the substrate. it must be deeper thanthan an inch. At thh deeper depth it is definitely anaerobic. Some plant will actually transport oxygen dow into their roots and release it into the subvstrate turning the area around the roots aerobic.

The result is there is amonia being processed ny the bacteria which use the ammonia and this ultimately creates nitrate. And then something interesting happens. In the anaerobic zones above and below where the nitrifiers have colonized, areas of denitrifyiers colonize and they process the nitrate. Not all rooted plants do this, but some do.

Of course, whe oe keeps fish that like to burrow into the substrate, that disrupts the distriution of whatever substrate one has unless rooted plants actt to deter that result. I am a believer when one starts a new planted tank the besy way to do it is to plants as one's first step, then the plants are allowed to settle in and start to develop a bigger root mass. This works to anchor the plant making it harder to uproot and it also helps to keep the substrate in place.

If one want only a thin layer of sand or no substrate at all and you want to have plants, one can always dp the plants in pots.

 

[Ceez]

I use about an 1.5-2" for all my tanks. No reason in particular except this seems like a good depth to keep from having any bare spots on my tank bottom and it's easy to get the python all the way to the bottom when cleaning. I used to put my caves down straight into my substrate but I've stopped doing that in favor of a piece of slate 1st followed by caves on top of that. This keeps the sand/gravel out of the caves for the most part and makes me feel better when they have fry in a cave. I also always keep sand/gravel butted all the way up to the top of the slate to keep food/debri from getting under it