my trigon 350 tank is currently running a rena cal heater,the tank was purchased second hand and thats what it came with,now some time ago i bought a brand new jumbo filter and 300w heater off of ebay,as you never know when they will come in handy,now there needed,my rena heater is starting to play up the tank temp. rises and my tank alarm keeps going off,i plan to put the brand new juwel heater in to replace the cal,now heres my question,the juewl heater has 3 full turns on the adjuster from the + to = settings,has anyone a rough idea where to set this to to start off with to try to keep the temp. at aprox 26?