I too live in a very humid place.
Houston.
Uggh...Right now the humidity is very high as I type this,like 96%.
I use the bigger Eva-Dry 500 and the smaller version branded as the Remington 365.
I am about to get rid of the smaller version because when I bought it last year it was such old stock and the last one Gander had on the shelf that even though they are wrapped in a blister pack the crystals were dark brown and required a charge before placing it in my Amsec BF.
Then it only lasts a couple of days so it obviously needs replacing.
The larger 500 easily goes 2-3 weeks before recharge is necessary.
I open my safe at least every day and it's not unusual if I do more than that.
I found a place online that sells them really cheap and at times with free shipping.
www.allergybegone.com
As a matter of fact excuse me as this discussion has prompted me to get off my lazy arse and order another 500 model.
Edit to add..Just ordered one for $22.99 with free shipping.