Excuse my ignorance - but what is a Powerhead and drip-plate

[Bubble_B0y]

I was wondering, what is a Powerhead.
I read many articles and they have mentioned it.
All I know is that it helps circulation and aeration.

Questions:

is a powerhead a filter on its own?
or
is a powerhead an attachment (does it need to be used in conjunction with another filter) ??


another question:

what is a spraybar and a drip-plate ?

do you buy it separately and attach it to a filter ??
or
do they come with a filter?

are they like airstones? do u need an airpump to operate it ??


sorry for the questions:
I use an aquaclear power filter/hang-on back filter.
They are simple and basic - nothing fancy.
They return water via a waterfall.

[fishyrican]

The powerhead is a small pump that sits inside your aquarium.

Here is a list of them:

http://www.bigalsonline.com/catalog/...2181;subcats=1

[Bubble_B0y]

Ok I just read that a powerhead attaches to an undergravel filter.
Question:
does this mean that the powerhead can power an undergravel filter - and hence you don't need an airpump to power the undergravel filter and you can buy a powerhead instead ??

Also, the powerhead has a function called REVERSE FLOW ??
what does this mean and what is so special about it ?

[fishyrican]

The powerhead would sit on top of the riser tube and pull the water through the gravel, under the [acronym:58d75a611c="Under Gravel Filter"]UGF[/acronym:58d75a611c], up the riser, and back into the tank. The gravel acts at the biological filter. Reverse-flow reverses the direction.

In any event, I would do some research on AA regarding [acronym:58d75a611c="Under Gravel Filter"]UGF[/acronym:58d75a611c]. You will see many posts/members that recommend against them.

[Jchillin]

And hereis the spray bar. Instead of having your water come out of the single output nozzle, by attaching the bar, you can "spray" it over a larger area of the tank.