In message , Derek Benson
writes
On Sun, 1 May 2005 15:02:38 +0100, sophiefishstuff
wrote:


my new (secondhand) tank came with a heater, which looks to be about the
right wattage for a cold winter's night, but rather overdone for the
summer... 35 (US) gallon; heater = 200W.

Is this a problem?

What I've usually seen on the spec sheet that comes inside the box
with a new heater is that the manufacturer recommends 3-5 watts per
gallon. This can also be found in various books and probably on the
Net. In my personal experience 5 watts per gallon is too much,
particularly in smaller tanks; and I'm talking about the heater
functioning correctly, I'm not thinking of a situation where the
heater gets stuck. Just for general use, these 5 watts are too
powerful.

I would never use anything stronger than a 100 watt heater in a 35
gallon tank.

Thanks for this, Derek, I appreciate it. I do wonder though if your
ambient temp might be a bit higher than mine? I'm in the UK and I don't
have the heating on at night or during most of the day during the week,
so from October - April I need a temperature hike of a _minimum_ of 8
degrees C and often more, and I wonder if a 100W heater would be
suitable for this? I'll keep a careful eye on things over the next few
weeks as the weather warms up.

If the weather is warmer (and I have to say it is not for many days a
year that the ambient temp. is close what I want the tank to be) won't
the heater just switch itself off? The original heater I had looked very
dodgy, so I got rid of it and got a (very expensive) Hydor Theo, also
200W... I take it you think this was a mistake ;-) The info on the box
recommends the 200 for the temperature hike I need and suggests the 100
wouldn't be adequate, and the fish-shop man agreed - he's someone I'd
trust, btw.

--
sophie

www.freewebs.com/fishstuff
(under construction. ish.)