Leaking Heater


Small Fish
Oct 11, 2011

I seem to have run into a rather frustrating issue regarding an aquarium that had recently settled and would have been ready for fish in the close future. I noticed a couple of days ago when doing my last water change that there were little flecks of what looked like gunk floating on the surface of the water; I was turning the submergable heater up and noticed the twisting bit and top cap of the heater (where the cable protrudes from) felt slimey. I cleaned this and thought the gunk was residue of the label that had been on the heater previously, thinking I simply hadn't cleaned it enough.

Well this morning I went to check on the water quality of the aquarium and see how everything was doing and noticed more and more of this gunk. I checked the top cap of the heater and it was slimey again so I unplugged it and removed the device. I checked other objects near the heater (I have an ornament with plastic plant foliage and wondered if maybe the gunk was melting plastic smears) but found everything to be normal so I took the heater downstairs.

I sat it in the bathroom sink and cleaned the slimey parts thoroughly, I also gave the glass tube a gentle go-over and decided to play it safe before putting the entire heater back in my aquarium; I attached the heater to the bottom of the sink (to make sure it would stay submerged) and filled it with water. I checked the heater thoroughly again and noticed that this gunk was exuding from the top cap and temperature adjustment valve - seems I have a faulty heater! I'm rather confused as the heater doesn't have any form of liquid in it and it may be that the cap is cracked and perhaps a seal beneath the cap is dissolving in the water or something, I'm not sure.

The heater is being replaced soon but I'm now concerned about the stuff in the water. I'll be doing a water change but am wondering if any of you have experienced this and if you know if this gunk is toxic. I'll clean the ornaments if need be but would rather not disturb them too much (sand substrate waiting to be capped and all). Obviously I want to do what is best for the future inhabitants of the aquarium.

Thanks for your time!

Last edited: