Thanks for the response. Realised it wasn't Prime that I added, it was "Stability". Silly me. It's been a long day, lol! Oh well, i did end up adding some of the old water and yes, there is a filter. I actually purchased the tank 2nd hand with some other fish in it which I added to my other community tank, but hadn't had the new tank on in a couple of weeks, so I don't know if any bacteria would still have been in there as the filter wasn't on. Today I cleared the old water out and put new water in. I also added live plants which were already in the betta bowls, so hopefully there should be SOME bacteria...
LOL - well the transition into the new tank went ok except for one major teething problem... one of the betta's managed to squeeze past the divider into the other male's section!!! Argh! Glad I was watching! I had the net ready to scoop one out, but they weren't fighting to begin with. They kept their distance and flared at each other, but no one was attacking. I wasn't sure what to do, and whilst I may cop some flak for saying/doing this, I decided just to watch them with the net in my hand for a minute to see how they would react. They danced around each other, but neither was being over dominant or attacking. I didn't want to risk anything happening even though they seemed relatively ok I didn't want to stress them out any more as they had only just moved tanks! We re-adjusted the divider, and so now it sits closer to the sides.
Once they had settled again, they both started to check out the boundaries of the divider to see if they could get through again, and couldn't, but would keep playing with each other through the net - the red one seems to fire up more easily to the blue one who flares up then turns his back and ignores him ;) lol... oh dear. I watched them for about an hour just to make sure they would be ok... i guess I will just have to keep an eye on them, I have never done this before with 2 males in one tank. Not sure if its the best idea, but I have 2 kittens coming soon and needed something with a lid, not to mention a larger tank (the bowls were always just temporary - def. too small!). Plus now they have a heater and filter... so yeah. Its a learning curve... if anyone else has advice I am all ears :)