Low porosity hair which tends to be heavy and loses volume.
I use cleansing shampoo, water based conditioner, hair milk, curl activator and gel for styling. I apply it all on soaking wet hair and scrunch it with a tshirt. Then I let it air dry a bit and blow dry it with a diffuser upside down. Also my hair is cut in layers. When I'm done I get the volume I wanted but shortly after my hair just looses all the volume. I need all the help I can get. P.s. I don't have dryness problems and I think my hair is very moist.
Try adding a bit of sea salt spray or make your own with epsom salt. You do have to make sure you use plenty of moisturizing products as this could be a bit drying but it sounds like you already are. You can use t at your roots (be careful if you are using a store bought one that it doesn't have silicones b/c that might make your roots coated and not give it the lift you want). I like Deva Curl Frizz Free Volumizing Foam at my roots and then a little hit of gel at my ends. My 1st day my hair tends to revert to it's more original clumps after fluffing. But 2nd day, it stays fluffed or volumized a little better. What are your products? Are you following the Curly Girl method?
I would try to either cut out that curl activator all together, or use less of each product you're using. Stay away from heavy creams and try to be light-handed with everything you use because these will only sit on your hair. Try adding the hair milk after your hair is 50% dry and make sure IF you MUST use a diffuser, that it isn't until your hair is nearly dry, about 80% or more. Also if you're using gel, depending on what kind it is, try using one that isn't heavy and has a light to medium hold. It honestly just sounds like you may have to tweak your products and how much you use. Especially if you have fine strands of hair.Hope this helps! xo