I don't think the Slap Chop and Magic Bullet were made for chopping meat or fish. Wouldn't you think the meat might turn into a protein shake? I wonder if anyone actually try chopping meat or fish with one of those yet.
Here is what I do for waterchange. I have location 1 and location 2 where my tanks are.
For location1, I put connect three 20ft hoses into a coupler to extend the hose into a 60ft hose. I masked the connection with masking tape to prevent any leaks. I know this is very ghetto way of doing it but it works.

I run a long hose from the tank outside to drain the water into the lawn. I preferred to recycle precious water than wasting it into the drain. See picture below. The hose is a 1/2" clear plastic hose purcahse from HomeDepot at $6 for 20ft. Once the 100g of water finished draining from the 150g tank I moved the hose to the 75g tank to drain. Now, I run outside to put in the black garden hose to refill 100g of water. While it's refill I'm doing cleaning on the 75g tank. When the 150 is almost done filling I run outside to shut off the water. I run back inside to move the black garden hose to the 75g tank to fill about 40g for water. I remove the silicone hose for draining and roll it up. I run outside to turn on the water until it's done. Water change for location 1 is complete.
With location 2 the fish are a little more delicate for I have to fill 50g of water into a trash bin mixing with heated water to get the temp close to 80F. It takes about 30mins to drain 3 tanks in this location and the 30mins allow the Prime Water condition to break down the chlorine. I start with one 20ft house to drain 50g of water in one tank, drain 5g in another little tank, another 10g in the 3rd tank. I remove the drain hose and put it to storage. I go grab a sedra pump and slap 1/2 hose over the nipple to pump water from the 50g bin into the tank. The pump takes about 30 mins to fill all three tanks. I think what I am doing is pretty effcient since I don't do bucket system.