Well, for the last 1 1/2 mos. or so, I was told that we only needed aobut 4 inches of water in our tank, so that wasn't hard to keep heated at all.
Our Tarzan (who I now think is a female) is about 1 1/2-2" and in a 20 long for now. Since we've raised the basking area, we now have 8 gals of water in it. It's over 1/2 full looking w/ the layer of pebbles, 2 bricks and filter.
One controversial issue that I'm not sure of, is that we have a strip therm on the outside at the opposite side of the basking area. We had a 75w Zoo Med (?) basking light that put off enough heat to keep it around 80-82°F.
I wasn't sure if this was def. too warm for a turt of his size or not, so yesterday we tried a 50w Dayglo. It's not heating enough at all, so I have to change it back for the 75w Zoo Med.
Does it sound like my 75w Basking light is good enough and a good system? Also, my husband said the 75w ZM bulb was more like a heat lamp where as this Dayglo is a regular type bulb.