Substrate Depth

[r4k]

I read somewhere that it should be about 2 inches but then some say that if it will not be a planted one, then substrate should be kept at a minimum or none at all, but i understand that beneficial bacteria that converts ammonia to nitrites then to nitrates will reside in the substrate.

so, basically, should substrate be kept to a minimum (2mm depth) or should i have more than an inch of substrate even though its not going to be a planted tank?

thanks

 

[minxfishy]

The bacteria doesnt reside in the substrate (unless you have an undergravel filter?) but in the filter inself or more acurately in the media inside the filter (foam, ceramic noodles).

The substrate can be any depth you like really, just a light covering up to 2" ish, alot does depend on the substrate itself (gravel/sand?) and whether or not you want live plants.

 

[rhostog]

As minxfishy says (while I was typing!), most of your bacteria will be in the filter media, not the substrate (unless it's an undergravel filter).

Some fish like to root around in the substrate (e.g. many catfish) or even bury themselves in it (some loaches), so you might want to think about what fish you're going to keep before deciding. If you spread the substrate too thinly, you'll find it shifts around every time you add water unless you're really careful, and you'll get bare patches. Plastic or silk plants often come with a base which you might want to cover up, and you might find it helpful to stabilise an irregular rock or driftwood if you can half bury it in the substrate. Plenty of people do without a substrate at all, but a good choice of substrate makes a lot of difference to how your tank looks.

 

[Rooster]

I have found that some fish "like" a substrate, so although you CAN run without one at all (no plants) it is beneficial to have at least a dusting... something for them to root around in.

 

[navvet8992]

if there is no bacteria in the substrate why does everyone say to get some of it from an established tank when starting up a new tank.??

 

[aaronnorth]

you can have some live plants in a tank without sunstrate like

anubias & java fern - these are attached to some wood or a stone

moss balls - these just roll around

floating plants - and these just float!

 

[Corleone]

if there is no bacteria in the substrate why does everyone say to get some of it from an established tank when starting up a new tank.??

Out of date advice, much like leaving the tank run for X days before adding fish or using salt to reduce stress. Undergravel filters used to be the norm, and in them, the substrate serves as the media where bacteria grow, so transferring gravel transfers the bacteria on them and jumpstarts the new cycle. But undergravel filters aren't as popular anymore for quite a few reasons.

Today, most filters are internals, hanging externals, or canisters, and some are sumps. With these filter types of filters, you want to get some of the biological media from the filter - either fiber, sponge, ceramic chunks or rings, plastic balls, etc. Generally it'll be the filter media that the documentation says never to replace.

There will be some of the good bacteria on the gravel, but not much. There's more bacteria there of a different type, which breaks down fish waste and actually releases ammonia, rather than removing it.

 

[Rooster]

if there is no bacteria in the substrate why does everyone say to get some of it from an established tank when starting up a new tank.??

"Everyone" ? I for one can tell you it does not ! Its a simple conclusion - the bacteria we want need oxygen, they are Aerobic... hence need a constant flow of oxygen rich water flowing past them, so unless you are using under-gravel filtration there simply isnt enough oxygen for the little darlings.