DIY Magnets - How Strong for 1/2" Glass?

[Harry Muscle]

DIY Magnets - How Strong for 1/2 inch Glass?

I'm building several DIY magnetic float switch holders which will use magnets ordered from magnet4sale.com (or somewhere similar). The thing I'm not sure about though is how strong the magnets should be to work well with 1/2" glass. Anyone used such magnets before with glass this thick?

Thanks,
Harry

 

[Delapool]

I can't comment much as only have magnets for holding co2 diffuser and glass cleaner. These I went for the best I could get as glass is 1cm and smaller algae cleaners just didn't work