saigaX

It certainly is freaky! Here's a pic for reference. Most of the time when we think of a crested loph, the first case with the single meristem comes to mind. From the look of it i'd say i wants to be polymorph/ monstrose. Only time will tell!

A bit harder to judge on the less "affected" ones, TMV usually has a mosaic pattern to it but it can appear at first, as many other viruses, as splotches. Eileen seems to be sun burnt to me, so give her filtered light and see how she does. TMV does not cause wilting/damage in such a sort period. Set up sun protection from the "affected" plants and give them some nitrogen/ magnesium . I hope it's not viral. Don't give up! Take precautions of course and isolate, just to be safe. TMV identification has become a bit of a fad/scare to first timers because of how similar it is to the frequent markings cacti get from overt sun exposure, nutrient deficiencies, bug bites etc. Btw do you have any opuntias expressing similar symptoms in your collection? They are infamous for carrying TMV! Take it easy

A cheap alternative to pumice could be perlite. Preferably sifted, so the more fine particles don't clog your medium. They do great in a simple soil mix with added perlite. Organics : Half coco / Half "beach" compost (which is full of fermented seaweed, shells, pebbles,sand and generally whatever i find on the shore) Inorganics : I go heavy on the pumice ~30% (it's great and cheap!) Some perlite for the sake of it. Zeolite and Palygorskite (a type of clay) in coarse grains to keep things... porous. Amendments : Gypsum and a bit of Dolomite for calc/mag. Mycos Trichos love their urea so pee, pee, pee! A good general fert does wonders.... then you can add calc/mag, b vits, micronutrients etc..