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Re: 150 watt substrate heater cables

> Date: Mon, 20 Aug 2001 05:34:39 -0700 (PDT)
> From: "S. Hieber" <shieber at yahoo_com>
> If you want these for planted tanks, go the whatever size smaller you
> can find--less heat is beter to ensure that the heater remains on most
> of the time--only slight heat is needed to generate convection.

I would disagree - go with the next higher size.

Less than optimum heat will cause the cables to be on for longer periods of
time (or constantly). The longer the cables are on, the more uniformly the
substrate is heated. A uniformly heated subtrate tends to reduce the
convection currents (no distinct warm and cool zones).

Also, if the cables are too small, you may not achieve the heat density
required to go from conductive heating (no currents) to convection heating
(micro currents).

I have a 100g acrylic tank that was originally set up for rainbowfish (76 F
water temp) with a 150w cable. I have another 100g tank set up for discus
(83 F water temp) with a 200w cable. I have a 120g tank set up for
rainbowfish (76 F water temp) with a 250w cable. All three work extremely
well. All three have been set up for five years.

A year and a half ago, we changed the 100g rainbow tank to an altum angel
tank (83 F water temp). Of course, the cable wattage remained the same
(150w). Things went downhill in that tank (fuzzy green ball algae cropped
up). Alas, the altums
didn't work out. Three months ago, we lowered the temp and went with pearl
gouramis. Now the algae has gone away and the plants are thriving again.

Lesson: for me, with my water conditions, my maintenace regime, my
fertilizers, my lights, my fish, my gravel, etc, if I don't have the optimum
(or higher) heat density, my results vary towards the bad. Your results may

George Booth in Ft. Collins, CO (booth at frii dot com)
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