50W Heater for 40 Gal Tank?

[j402]

I know I Need 300W Heater for my 40 gal tank, but I just upgraded to 40 Gal from 15 gal and I have 50w heater. so until I get 300w heater (after saving up money ~ 6 months), is that ok if I put 50w heater in 40 gal tank? it's winter and my tank is close to door, so temp might fluctuate a lot. I want to keep it around 75F for my goldfish.

Thanks......

 

[CaptainAhab]

can't hurt, prob won't help much though. IMO a 150/200 would do you fine. 2 never hurts either.. one as a backup

 

[WhiteDevil]

J4, petsolutions.com has heaters cheap. easily 50% off retail prices.
(marineland visitherm stealths for under 25 bucks,all sizes)
Visi-Therm Stealth Submersible Heaters, Heaters | Pet Solutions

A 50 will run constantly and possibly burn out prematurely.