I had 282 gallon system not including the sump system. I wanted to use 1600 ml total but since it was the initial start, I had to start with just 550 ml and waited 3 weeks. Then added another 550 ml and waited another 2 weeks before adding the rest.
Don't get me wrong, it's a horror to start bio-pellets in a high nutrient system. It's definitely growing pains like cloudiness, bio-slime coating the glass in a day or two and it literally took 3 months before the No3 even dropped 1ppm. After what I guess is the break in period, the No3 started to drop fast.
Since I started using the pellets in one of my systems, (4 years) I tried to stick with the initial brand but started to find that it was not easy to get. The first 2 years, I was able to stick to the brand but then started mixing with whichever was on sale since my system consumed 500 ml every 3 months. What I've learned from the last year or so is that Eco-Bak does make a difference in the tumbling department. It by far has been the only brand that I have used that does not clump on me. All the others would clump after 2 weeks and I would have to play with the flow rate, shake the dang reactor violently and just wait until the phase passed. I have not experienced this annoying habit with the Eco-bak but it also has not moved my Po4 numbers either.
I have a bag of the All In One pellets that is supposed to reduce Po4 twenty times the amount of regular pellets but we'll see. I have a feeling that I will go back to Eco-Bak primarily for the non-clumping issue. (The problem with clumping IMO is that it throws everything out of whack. The tendency is to increase flow by a lot to stop the rest of the pellets from clumping but as the parts that stay un-clumped gets tumbled too fast, the bacteria that you are trying to cultivate gets sheared off too quickly and etc., etc)