# 'Submersible' heaters



## mfgann (Oct 21, 2010)

So my marineland visitherm heater had a couple of inches of water in it, which I decided couldn't be good. I headed out to petsmart to pick a new one. I avoided the marineland stealths with the rash of exploding heaters they've had, and went with the Fluval M series. I got it home, popped it in there, and then read That I should be careful not only to keep a minimum level of water, but also not to submerge it below a maximum water line as well. Whaaat? What exactly does "submersible" mean? I mean, some part HAS to be submersed to heat the tank, right? So submersible should mean all the way under, right? Right?

Weird.

Oh, and they had a little Marina Cubic 0.9G glass tank on sale for $16, so now I'll beaslbob it and have a little shrimp tank at work.


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## Gizmo (Dec 6, 2010)

I've read the same thing on my Rena Cal 100W heater.

I think they're suggesting you keep the very top temperature adjustment part of the heater out of the water, but keep the majority of the heating element in the water to avoid screwing with the temperature sensors and possibly causing a meltdown. My assumption here is that they want the part that isn't sealed water tight to be kept above the surface to avoid the potential for water to get down through the moving parts and ruin the heater.

Thoughts, anyone else?


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## jrman83 (Jul 9, 2010)

I have one of those heaters on my 75g I think. It's submersible, just not 100%. Mine has a min/max water line drawn at the top of it. Funny thing is, I mount all of my heaters the exact same way on all of my tanks. The very bottom of the heater is where most of the heat is anyway, and in all cases that area is below the middle of the water column on my tanks. I have always just felt funny about putting heaters in water past the power cord area, not sure why.


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## mfgann (Oct 21, 2010)

jrman83 said:


> I have one of those heaters on my 75g I think. It's submersible, just not 100%. Mine has a min/max water line drawn at the top of it. Funny thing is, I mount all of my heaters the exact same way on all of my tanks. The very bottom of the heater is where most of the heat is anyway, and in all cases that area is below the middle of the water column on my tanks. I have always just felt funny about putting heaters in water past the power cord area, not sure why.


Yeah, me too. I am just used to the old school style that weren't meant to have any part of the top below the water line. I'm mainly griping about it either being a marketing term or they discover a problem, and rather than fix it they add a label and warning. I guess I just wonder why I paid $30 for a heater that has the same stipulation the $5-10 dollar ones did.. and these are 'harder' to keep above the water line since they suction cup inside the tank, rather than hang on the rim.


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## Mark13 (Oct 21, 2010)

Stealths are fully submersible, as are Tronics and Rena's, and several others. I contacted all of them when I read a Stealth box that said "Submersible", but the instructions said both "Sub" and "Not". All of them said they are fully submersible, even to the point of mounting them horizontally in the tank, which the instruction sheets showed a picture of as being OK. They said any mention of "Not" was incorrect on their parts.


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