Fluvall e300 Heater Problems

[Fishmutt]

I know there's another thread on this already, but it says I can't reply to it because it's 153 days old. http://www.aquariumadvice.com/forums/f60/fluval-e300-heater-junk-178774.html

I am a rookie at the aquarium hobby so I don't have any great advice, but I did want to document some of the good and bad as I set up my first tank. I have a 90g (+10g w/d filter) for a tropical freshwater tank. No fish or plants yet, started cycling 5 days ago.

I set the heater horizontally in the 10g sump next to the pump. It seems pretty good spot since the water has to flow across the heater to enter the pump.

1. The first problem I had was the heater allowed water and/or condensation into the display. After about 3 days the display clouded up to the point I could see the color, but couldn't read any numbers. I'm hoping this didn't allow something nasty like mercury to leech into the water.
2. Second problem is the heater did not heat the water. The heater warmed up the first few days, but after that it was always cold to the touch. I am wondering if this was related to the lack of watertight seal, or if it's because it's horizontal, or because it's in a low flow area. My home temp is set between 70-74.

I just got back from returning it to the fish store and getting a replacement. I hope the first one was just a fluke, but I will follow up on this thread either way.

If anybody else has horror/success stories, or just general advice about the e300, please share.