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Re: heating cable duration

>From: "Chin See Ming" <chinseeming at hotmail_com>
>Subject: Re: : heating cable duration
>I think your basic problem is using a heater in Singapore.  It doesn't look
>like you've got the tank in an air conditioned room.  Given that your
>ambient air temperature is going to be around 26 to 28C (approx. 80F), I
>don't know how you can use a heater at all.  I think a chiller might work
>better . . .!  :-))
>More seriously, I've never been able to figure out the premise underlying
>(pun intended!) substrate cable heaters.  If it's to create a temperature
>differential between the substrate and the water column, there already is
>one:  the substrate is typically colder than the heated water column, at
>least in temperate countries when it's not summer.  If it's just to heat
>roots . . . well, you don't need to in Singapore.

this is my own theory . . . if the substrate is cooler than the water, 
there will be no induced water movement due to convection . . .
cool water tends to sink, while hot water tends to rise . . . to induce the 
water movement you will need a warmer bottom . . . mayhap the same reason 
why they place the heating elements for kettles on the bottom . . .

i'm already doing the heater timer rotation, but the temperature is still 
at 31.5 degrees celcius . . . i will be getting a fan for the tank
soon . . . and hopefully the temp will drop back to normal . . . i agree 
with you on the root heating part . . . but heck, if i'm going to redo a tank,
might as well go all the way high tech :) . . .