@Jeebusai
I have done the below testing, hopefully can give you some ideas...
My conclusion is that ice bottle can only help bring down the temp, but to keep it constant I guess still need fan bah... so fan + ice bottle should be able to help provide a lower temp....
Test 1
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Outdoor Temp: 30c to 33c
Tank Start Temp: 31.8c
Tank End Temp: 30c
Ice Bottle A:
- 500ml (Ice melt completely in 20+ min)
- Temp drop from 31.8c to 30.9c within 1hrs, and stay
Ice Bottle B:
- 500ml (Ice melt completely in 20+ min)
- Temp drop from 30.9c to 30c within 45 min, and stay
Test 2
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Outdoor Temp: 27c to 30c
Tank Start Temp: 32c
Tank End Temp: 29.9c
Ice Bottle:
- 500ml x 2 (Ice melt completely in 35+ min)
- Temp drop from 32c to 29.9c within 1hrs, and stay
**Bottle is put inside a plastic bag and fill up with water to cover the bottle as to provide a cooling factor