Hey guys, my experience w/ my DIY SIPS, all types, can incur two different stall types for two different reasons.
Type 1 stall, a two week stall-out that takes place when I transplant into a SIP from non-SWICK/SIP seedling pot, just traditional 2-3 gal. Best way to avoid is develop a SIP/Seedling system so you grow good water roots by transplant
Type 2 stall, when I fail to transplant before node 5 matures, I get an Eterna-Stall, regardless how I raised the plant thus far, even transplanting 6 node plant that's been bottom watered or in baby SIPs still experiences a mega stall and overall performs poorly yield-wise.
There's no growth in type 2, seemingly forever, or, its ultra-slow for ages and this is when root rot can really set in quickly. Roots need to constantly grow and shed the old, used 'skin'cells just like us, and like us require invisible microbes to clean it away. If growth stops the roots immediately become prone to rot as this constantly dying root matter still builds up and if you don't have beneficial bacteria that will eat it, harmful fungi will, and root rot proceeds from there.
Have some bacteria or enzymes on hand that keep your rhizome healthy by cleaning roots and turning the excess into mineral plant food. I use a drain cleaner/septic field bacterial treatment product because it has all of the beasties my rhizome needs and its a helluva lot cheaper and way more powerful than dedicated canna bennies. I also recommend and have used these bennies, Real Growers Recharge (seller of grow dots time release nutes and a new 5-gal SIP setup), and NPK Veg microbes.
NPK gives you a lot of nice Subtilis, Trichs, Streps, Brasilineses and EndoMycos - and their separate Flower Microbes focus on multiple phosphorus solubizing bacteria. Love both.
Everything I recommend ships as a dry wettable powder, so has long shelf-life, except the Septic cleaner stuff is affixed and dried on to a very finely ground seed bran, just like Bokashi, except orders of magnitude more powerful and much finer bran. It has excellent shelf life also.
However, I started producing a special canna-tuned vermicompost where I feed the worms on home-grown accumulator plants and special additives (nettles, comfrey, seaweed, horsetail, neam cake, ground oyster shells, psilocybe cubensis mushroom-grow blocks already harvested - super high in calcium and L-Aminos - powdered eggshells, mycorhizae, local microbes from forest loam, and a few other choice additives that make my worm poo ultra-power-packed, including spraying worm trays with a mild GreenLeaf Sweet Candy mix to feed the microbes even more... Nowadays I use teas from this vermicompost to douse my root system with micro-fauna. I hear Great White is good also, I think
@RedskinnedRhino dumps it straight into his reservoir fill pipe.