how small can you go???

+1 forgot about that lil nugget of wisdom!

 

a small filter will not add enough volume to make any difference unless you do an insanely overkill filter. on such a small setup a filter is nearly as unnecessary as a skimmer is. sure they can be on the setup and wont have any negative effect but its really just an unneeded piece of equipment.

 

You can use the HOB to add other things then filter media such as cheato to help with algae/nutrient control. Any extra volume of water you can add to a set up is better then none. Also, the HOB filter will add flow so you don't have to worry about a power head or anything like that as well. Even if you just run carbon in it to polish the water, it is still beneficial. ;D

 

What about this for a Nano or Pico tank?

http://www.amazon.com/Zoo-Med-External-Canister-Filter/dp/B005DGHRU2

 

umm you;re adding volume to a tank that has little, and its inhabitants are prone to the very easy to have param changes of a smaller tank! A little bit of nasty(toxin) etc can hurt a small tank quicker than a little bit in a bigger tank! I just don't see the downside to it! Plus why do you want to look a air stone in a reef tank and deal with it splashing water everywhere?

 

+1 Filters are beneficial wheter it be 1 cup or 100 gallons every little bit helps.

 

I think that could work. You could put some Rowa Phos or purigen in there to really help. The Purigen would help control ammonia and nitrites as well. ;D

 

+1 picos or nanos are pretty neat there are lots of cool little tanks out there

 

I'll be buying the 501 filter and making a light out of two CREE LEDs in the next few months.

I really like the JBJ Picotope.

 

yeah that should work, what size are you going with again?