by 6 do you mean 16?

No. I mean six inches.

I am planning a sump. 6 inches. very interesting. thank you.

I think this is roughly 6".

http://i1002.photobucket.com/albums/...5A212DC8D5.jpg

It's totally doable. Whether or not you'll enjoy it is another matter tho :-)

But if you are planning a sump that means you'll probably want a skimmer and possibly reactors and stuff like that. That means your sump will likely be much larger than 6". Probably 12" at a minimum. In that case go as deep as your space will allow.

I would go 18" at the absolute minimum. If its an 8 foot tank, you should really try and get it up to 20". Getting good flow can be really difficult in thin tanks. Without good flow you can get some nasty nitrate problems later in the tanks life.

Mine it is 7 foot tank .
It is 22 inches wide and probably 16 would be the minimum
My tank is only 20 inches high which give it a long sleek look

8 feet long any less than 18" will look so out of proportation.
My tank is 24" deep and wish it was deeper!

So let me get this straight. He wants to keep a reef aquarium with anemones and clownfish and you believe 6" would be enough? Interesting...

I have seen lots of nano and pico tanks with clown fish and anemones that were about 6". So ya it's doable. The fluval spec is about 6" and there are some interesting things done with them.

http://m.youtube.com/watch?feature=r...&v=Lzr3EyyXs10

Edit: clown fish&anemone in 6" tank:
http://m.youtube.com/watch?feature=r...&v=gM4Gvb716_U

Don't you feel that with 3800+ posts that you should be promoting slightly more ethical and sustainable practices? Placing fish that grow to 4-6" in a 6" wide tank sounds a little ridiculous to me. Even a bubble tip anemone could occupy over half of the cross sectional area of a 6"x18" tank.

From your video:
"2Gallon is way too small for nemo!" ~viewer
"I thought so, but it maintained for more than 8months. and now it's gone. thanks for your comment." ~owner

Great 8 months, really impressive.