filter and heater question?please help

[Carny_4_Life]

ok i have a filter rated for a 30 gallon tank and a filter rated for a 60 gallon tank on my 20 gallon hospital/qt tank which houses my oscar that i just got
and the heater on the tank is rated for a 30-60 gallon tank
is that ok or would the heater fry my fish?
i got a smaller version f the heater that's for tanks 10-30 gallons BUT you can't lower or raise the temp on it and it only gets the water to about 70
it wories me because i think he should be kept in the mid 70's
but i don't wanna fry him
and is to much filtration bad?
could it hurt him?
or is it good for him?
any advice is much appricated guys and gals
thank you

 

[Bderick67]

your heater is equiped with a thermostat, if set properly the heater will turn off once it reaches the desired temperature. The filtration you have is not too much.

 

[ercnan]

As long as the heater works properly it will be fine.
If it sticks on, you have dinner. If it sticks off you have a frozen dinner.
I'm joking of course.
Any heater can fail either way. The best way I've found for them is to put 'em on a controller that shuts them off despite their internal thermostats.