1/3 HP Sump Pump?
Answers:
Everyone is forgetting that the head pressure is increasing as the water level drops.It'll actually take longer to pump a gallon the more that's pumped out. Also, all pumps are not created equal. Some have a higher GPM than others and that too varies from model to model as head pressure increases. It won't be 11 feet deep , it's likely at most 8 1/2 feet as that's standard, no more than 9 feet if they goofed a bit in construction and is likely a 16X32 or 18x36.
About the only way to get a rough idea is to measure the current depth, check an hour later, take that and divide it into your remaining depth. It's only gonna be apporximate, that's the best you can do. A lot can vary just by how flat or curved the pool hopper is.
Other answers:
A 35 inch by 15 inch pool that is 11 foot deep is a strange combination That is more a shaft than a pool.
Assuming that you are reducing the level by 6 inches every 8 hours and assuming that you started with 5.5 feet of water, it will take another 80 hours to remove all the water.
You are removing one foot of water every 16 hours. Seeing as you have already removed 6 inches, you have 5 feet left to remove. 5 X16= 80
A 35 inch by 15 inch pool that is 11 foot deep is a strange combination That is more a shaft than a pool.
Assuming that you are reducing the level by 6 inches every 8 hours and assuming that you started with 5.5 feet of water, it will take another 80 hours to remove all the water.
You are removing one foot of water every 16 hours. Seeing as you have already removed 6 inches, you have 5 feet left to remove. 5 X16= 80
35 in by 14 in by 11FT deep?
Can you imagine what this looks like?