The float test is notoriously unreliable. The best test is to run fingers from tip to root, if it feels really smooth and possibly squeaks, it's low porosity. LONG drying time is also a symptom. Back in the day, when I worked and didn't use products, I'd show at 6, squeeze out excess water and towel dry, diffuse for a bit--and go to work. At 11:30, the under layers would still be damp.
3a (Corkicelli), highlighted, fine, low porosity
modified CG, since April '07
CG since 3/11/08

SE PA

HGs: Anything Sevi; Curly Kinks Satin Roots, Curlycue ReNew and Coil Jam; homemade FSG and okra gel; soap bars; UFD Curly Magic; Botanical Spirits Jellies, CJ Repair Me, Marie Dean Leave Ins and Curl Creams