Best depth to put canister intakes?

I have always put my canister intakes very deep, most cannot go deep enough, but I do as deep as they will go. Is this the best situation? What do you guys use? Or do you use surface deep?

 

I'd say the deeper the better. Dirt aso will "collect" in the lowest waterlayers.

 

Fluval recommends about 3" from the top of the substrate or bottom of the tank. I assume this is to ensure that there is adequate space around the input to provide the maximum available water current and not suck up any substrate.

Plus if things go south there will still be about 3 inches of water left in there too keep the inhabitants wet and alive.

That too.

 

Plus if things go south there will still be about 3 inches of water left in there too keep the inhabitants wet and alive.

 

Will it still pick up the dirt on the bottom?

 

I have them just below half the depth, so that they don't pick up muck from the bottom, and I can do a 50% without having to switch them off. I prefer to take the muck out myself and keep the media clean(er).

 

It will never pick up all the debris, ever. The goal of filters is to create enough current to keep the waste suspended in the water column providing more time for the filter to collect it.

 

It will never pick up all the debris, ever. The goal of filters is to create enough current to keep the waste suspended in the water column providing more time for the filter to collect it.

Not really. You would need a very powerful filter, and very little if any decor, to keep solid waste suspended. Most fish would not be comfortable with that much turbulence. As long as there's a fast enough throughput to remove ammonia and nitrite as they're produced, you have an efficient filter. Solid waste increases the load, requiring extra bacteria, and is best removed from the system with water changes and substrate hoovering/cleaning.