How Many Heaters?

[rixy]

i have a rio 240 tank with approx 20ish malawis.set up my external eheim 2028 approx 7 days ago.was doing a water change last night when i thought " christ thats cold".looked at the thermometer and it read 22c.lifted out the heater and you guessed it,broken.got down my lfs just in time to get a new jewel heater.the old heater was 200w and the new one is 300w.my main question is,with the external running,will i need a extra heater???the eheim 2028 is very powerful and is rated for 130 gallon tanks.i'm just worried with the amount of water passing through the external,can 1 heater keep it warm

 

[simonbrown403]

I don't see why not, the rule of thumb is 5watts per gal so a 300watt is more than enough.

In the end the filters only circulating the heated water from your juwel internal filter, if you just have the external then that will circulate the heated water around the tank and trough the filter.

 

[rdd1952]

The 300w should be enough but as a general rule, on large tanks (4' and longer) it's best to have dual filters and heaters for better circulation. If you set the temp on 78f and put it on the end where the filter outlet is, the other end of a 4' tank could easily stay 2 to 4 degrees cooler.