In a very large bowl, weigh out the water and the starter. Using a whisk, stir the mixture to combine. Ensure that the remaining lumps are completely dissolved. You may use your hands to dissolve any remaining lumps.
Add bread flour to the starter mixture. Using the dough whisk, incorporate the dough into a sticky mass. Switch to your bowl scraper and finish combing the flour into one homogeneous mass. Cover and let rest for ten minutes.
Meanwhile grind the salt into a fine powder. You can use mortar and pestle or spice grinder. After 10 minutes are up, dimple the dough with your finger and add the salt on top.
Complete knead #1: Fold the edges of the dough up and toward the center for 30 folds. Flip dough over, cover and place in a warm place and let the dough rest for 10 minutes.
Loosen dough with scraper, Complete knead #2: (30 folds to the center),flip the dough over and let it rest for 10 minutes.
Loosen the dough with scraper, do Knead # 3: (30 folds to the center),flip dough over and let it rest for 30 minutes.
After 30 minutes is up, loosen the dough from the bowl, with wet hands, complete 6 stretches of the dough- pull the dough 6 inches up and towards the center, rotating the dough as you go. Complete 6 stretch folds, flip dough and cover. Let dough rest for thirty minutes.
Complete a series of 6 stretch folds 3 more times with 30-minutes rest at each interval. The dough should have now rested for two hours and doubled in bulk.
Meanwhile, prepare the bannetons/proofing baskets by dusting it with flour,getting into all the grooves.Alternatively, use the provided linen cloth cover. Complete a light dusting of the cover with flour.
Divide the dough in half and form into round or ovals depending on the shape of your banneton.