Yeah, I thought that the rush of water from the bell siphon would be a fun thing for the fish. Sounds like your fish are fine with a lot more sudden flow than I've got now.

On the question of fishless or fished cycling, it got a bit complex. I got the system cycled with a fishless cycle. Then I got a gold fish to make sure that things were cool. Then a raccoon got into my system and knocked over the GB feedpipe and drained all of the water out of my system killing my gold fish. I then re-established the cycle with the dead goldfish as an ammonia source. The goldfish had been dead for a good 2 weeks before I got the Koi.

I did not salt bath the Koi as soon as I got them. I just let the bag sit in the FT to let the temperatures equalize and then slowly mixed the tank water into the bag water and then I let them go in the FT.

I read that for ich, the salt treatment should be 12 hours in 6ppt salt bath, then 12 hours in 0ppt salt bath. Repeat 3 times and ich should be gone. I've read that salt bath is good for most other illnesses as well, so I just followed the ich instructions. After the first death I reduced to 3ppt salt for 12 hours. Second fish did not make it through the first 12 hours either.

Lots of aeration in the salt bath/hospital tank. Not a cycled system though. I was planning to change the water out every 12 hours, so I thought I might not need a filter... anyway, I don't have a filter on hand and it will take me a day or two to get one.

I'll check the chemistry in the hospital tank and see if it got too out of whack. Maybe that is what killed the sick fish?

I guess I could have introduced some sickness with the gold fish that didn't die completely with the 2 week no-live-host period. Also it could be that I got a batch of sick fish from the get-go. I got them from ebay seller "nextdaykoi". They have a very high rating and they have nice stuff (at least to my untrained eye). Still, the poor buggers got shipped from North Carolina to San Francisco, so that may have been just too much for them? I was planning to go with a different supplier next time if only to cut down on the travel distance.

As for aeration in the main FT... that was my first thought and I put a couple of stones in there to make sure there was enough oxygen in the water. The stones had no effect on the death rate or fish behavior that I was able to see. The system is an ebb&flow system with an 8 minute cycle and I've got a venturi air mixer on the GB feed pipe. Now the system has approximately 0.1 lbs of fish in it, so when I setup my hospital tank, I figured the the oxygenation in the FT was cool and the hospital tank was where the aeration was really needed, so I took the stones out of the FT and put them in the hospital tank.

Thanks,

BB