I had 7 buckets connected and was having slime issues throughout. I run em individually now. It's more work but you don't have to worry about your water going bad just cause one plant.
Where were all your problems coming from? One thing I did before I even setup my dwc was scrubbed everything with Clorox and sprayed Lysol. I made sure my water temp was at 75 or below.I always changed my nutes every 7 days.