Hi acg85 ...Welcome ! I am also a newbie when it comes to container growing. Because I am planning to do some container/pots planting , I have been educating myself in this forum. ABOUT COLORANTS: I think you are talking about colored mulch which may or may not be mad of pine. I have used them as landscaping mulch. If it is made of pine, it is shredded and made from pine branches and trunk that probably was not suitable for making lumber. Or can be made from the next layer under the bark. It can also be made similarly from cedar or other wood. They usually come in red and black color. Pine or fir BARKS are mostly bagged and sold uncolored. That is what they are using in 5: 1:1:and orchid potting mix ; ALL NATURAL PINE BARK (NUGGETS,)

I've been using a 50:50 base mix of perlite/ turface for many years. You can easily modify this mix for different needs. Most mesembs benefit from the addition of a clayey component. For me, I just dig beyond the topsoil in my yard for some good dirt. I also substitute perlite for some lava rock and small pebbles. It's a heavier, longer lasting mix which works when repotting infrequently for mesembs. This same mix is my preference for small cactus species like Aztekium, Blossfeldia, tricky mamms like luethyi, etc. "bigger" plants like some Crassula, aloes, aeonium etc. you could add more perlite to lighten big pots. It also makes it safer to leave outdoors all spring/summer/fall with rain. My palms, plumeria and cycads live in this mix too. Floating perlite is not an issue. But it does easily displace with high water pressure like from a hose. Some form of fertilizer is a must. I'm also a fan of submerging small pots with small plants into bigger, deeper containers to help stabilize root temperatures. Practically any healthy plant I've ever had to repot always has roots circling the bottom. I really don't understand the concept of shallow or regular pots. I think the deeper the better. I haven't really noticed any exception. For some species it's mandatory. Haworthias, many cactus plants with tuberous roots. Even Lithops which tolerate a shallow home will grow much better in very deep pots. Pleiospilos too. For anyone unsure or unconvinced, try an experiment. Take a pot with any plant you want, and bury it into much deeper pot for a growing season. Pull it out later and see what you find. Bury an Aloe, pachypodium or most any strong Echeveria or similar in the garden and watch it take off. We would all be great at bonsai, plenty good experience with root constriction and limiting growth lol!

The larger the size of the particles, the faster water will pass through them, so you won't be improving water retention. In my experience, turf ace seems to retain more water than fir bark. If you're concerned that your bark is too much larger than the other components, it would be better to eliminate it so you have a 50-50 mix. The key to the gritty mix is uniform particle size. Have you tried gritty mix following the recipe as closely as you can given your bark size? It's really worth doing that and observing the results before altering the recipe. Have you tried the 5-1-1 according to the basic recipe? I really like it for most of my plants. The exceptions are most succulents and plants that are sensitive to even slightly soggy soil. If you're nervous about a mix with little or no organic matter, try the 5-1-1 first.

Yes, there is a lot of dust in the bottom of the bag. Last year I screened out the dust using a huge strainer basket/bowl thing I found at the asian grocery. Didn't think about using the dust instead of peat. I'll try doing that with a few containers and see what happens. I'm going to go over and get a car load of pine fine bags this weekend - planning a big container veggie garden this year.