The 50w gu10 will be (in my perception) about 3 times brighter, but burn a lot more energy and produce a massive amount of heat. I cant exaggerate that one. Massive amounts.
I swapped the GU10's in my house ceiling lights for 1W led lights about 3 years ago and the light was far better than expected. During the day, its a bit like filling a fish tank with a water pistol, but when you actually need them, really decent.
so baring in mind that they are only going to be a few cm away from the tank glass, the heat from the GU 10 might make them a bad idea?
there will be 3 of whichever bulb i go with to light a 3ft tank.
really glad i asked now, felt like a silly question at the time but i hate to think what the consequences would have been otherwise. i had not thought about how hot they would get, don't think i've ever used halogen before.
think i'll invest in a tabletop lamp to sit beside me and use the GU10 in there instead of putting the heating on
thank you very much for helping and advising