Poisoned Water?

[shockshockshad]

Whats the mechanical filter and bio filter?

Mechanical filter is the sponge material that gets rid of things like dirt, and really just all that brown stuff, and biologial filter is bacteria that eats fish waste. there are 2 types, 1 that processes ammonia (fish waste) and turns it into nitrite. the 2nd type processes nitrite and turns it into nitrate. to get rid of nitrate, you do water changes. But to get this bacteria, you must cycle. heres a link : cycling. you may or may no have chemical filteration, but it removes smells, chemicals, and sometimes ammonia (zeolite removes ammonia). usually chemical is activated carbon. change mechanical (sponge) every 2-4 weeks- use 1/2 old sponge & 1/2 new, chemical replace every month, as it gets worn out, and never replace biological- rinse it in old tank water. NEVER TAP WATER. Hope this helps.

 

[vinylman]

With the 13 fish i have, what would be a suitable size, In your opinion?..

Go for the biggest tank you can afford and have room for (and of course a proper cabinet/stand made for the job). You're not the first to be given cack advice by a LFS and you won't be the last, unfortunately. BTW, are those live plants or artificial - you can never have too many live plants. Keep firing your questions, you'll get the right answers here.