I am on my second season of using Fiber Clear brand of cellulose fiber in my Hayward Micro Clear DE Filter. I like many made a couple of mistakes along the way like using some of the chemicals that I used with DE.
I will never go back to regular DE although many have posted that they are not happy with Fiber Clear. Many of the users frustrations are around issues such as algae buildup or use of chemicals like classifiers. Part of the problem is that the Fiber Clear folks don't do a good job of explaining this on their package. You have to read through forums and go to their website to get the skinny. I wish I did before making mistakes that cost me time and money. They would probably sell more of their product if they invested in helping the pool user maximize the effectiveness.
The reason I will never go back is because it does a better job keeping my pool clear than DE by filtering down to 2 microns, I don't need to spend money on chemicals such as algaecide and classifiers. All I really need is Shock, my Nature 2 sanitizer and a low level on my inline Clor Tab.
Because cellulose products filter out smaller particles the biggest complaint people have is that you do need to backwash more frequently when opening your pool up. This happens quite frankly because it is catching the particles faster versus DE so when you really look at it you would have to run your pump for more hours to remove the same amount of particles. I do find that during this process I have to backwash a little longer time period but it rinses the Fiber Clear out really well. The only time I had to spray the grids off was the first year when I used the other chemicals. This season I inspected the inside of the filter after doing the 3rd backwash and there was very little residual material on the grids. What was there was primarily in the gaps where the stitching is at the top and not the grid surface. In previous years the DE would be caked on the grids after opening and I would have to spend a couple of hours properly cleaning them. The key is to watch the pressure and backwash when the pressure rises. Last year I only had to backwash 2 times during the season and this is a pool that gets heavily used and abused.
Some people say that if you have a lot of algae in the pool that gets trapped in the Fiber Clear that simply pouring liquid chlor down the skimmer will kill the algae in the filter. I have yet to experience this issue yet. I also like that I use 1/8th the amount of Fiber Clear versus DE and it is easy to charge my DE Filter from the skimmer.