My husband and I have experienced the same fish kill (all dead within 12 hours) problem with our newly divided 30 gallon FW
guppy breeding tanks and have narrowed the issue down to the GE Silicone II. Darn it!
Since you experienced this back in 2010 I'm guessing you have long since resolved the issue. I have a few questions I'm hoping you can assist with.
1. how did you remove all of the bad caulk? razor blade? chemical spray <I shudder to think adding another chemical is a good idea>?
2. We have airline tubing and nice foam filters in these tanks that I'd rather not re-buy. Did you have to replace all tubing or filters, media? or were you able to save these with some sort of cleaning? If so, how?
If you have any other thoughts or comments to share on this topic, I'd love to hear them!
If anyone else wants to weigh in on this, please do!
Thanks ever so much,