ph 6.2~7 should be fine for fishes. less than 6 means ur water more acidic, more than 7 means alkaline. and why put salt? your fish is sick? never heard of that salt too. if its healthy just aged water/chloramine will do fine.

if its the suitable size of your tank u're asking about, i'll say the larger the better. most people like to keep betta's in a dang small jar. which is bad for the fish health/liking. nobody likes being cramped in such a small space right? even thought it's a fish, well, you will want ur pet to be happy right. its really up to u. but personally i use a 10 gallon tank. its planted and filtered.

lol, yea it's bit too large for 1 betta. so i keep some shrimps alot with it. plenty of hiding place so not much fighting or eating each other cases.

sigh... never said a bigger tank must be better. already stated its personally i use a 10 gallon tank and its up to u to use what else. indeed ketapang leafs proves good for bettas. but if its about salt. check these out.

http://www.fishlore.com/fishforum/betta-fi...read-first.html
http://www.arofanatics.com/forums/showthread.php?t=28044
http://www.arofanatics.com/forums/showthread.php?t=182745

above got enough guides all bout betta keeping. betta's are freshwater fishes. salt proves to kill bactiria and helpful to get a sick fish back to healty. but non use it for long term water. only use when needed.

so what this line means? u use salt for keeping or not? if not but use only when fishes need treatment y say i am wrong?
you read my 1st line but not the following, 'its really up to u. but personally i use a 10 gallon tank'.

is it my or your english fail? yeayea whatever. i given a few links to those who need help. i find them useful and agreed by many. as for u, think what u like, u starting to bore me out.