The tank temp varies as I manually adjust the temperature during colder months.
Generally I raise it to about 26 C then let it slowly fall to about 21 C. I then repeat. I find it costs me less than maintaining a steady temp.
In warmer months I monitor it regularly and just make sure it is above 21 C. I don't have a problem with it getting too hot regardless of the outside temps as the insulation to keep it warm in the colder months also keeps it cooler in the warmer months.
By keeping cooler temps the fish appear to generally have longer life spans.
indeed, my 125G tank looks so tiny compaired to these tanks but its ok! I do super heart these tanks though, i watched a lot of stuff on your youtube channel