My starter is very acetic; how can I develope a sweeter starter? I know I have to develope more Lactic acid...how is this done?
What temperature are you keeping your starter on? Any temperature too much away from 30 degrees C (this is optimal for the yeast activity) gives too much sourness. You already may have too much lactic acid if not incubating your starter at around 30 C.
No, what you can do increase more feeding.I have my starter over 17 years old and is on the counter all time and what will happen on the top you will get black water that protect the starter and the starter go down as the clay. When you need some just mix that liquid in and spoon how much do you need and put there some flour and water and cover it. That portion you took out mix with flour about 2-3 feeding and that starter will be weaker with more flour and the water.
How can you make it less acidic? Give it more to eat :) Either feed it more often, or with a higher proportion of flour/seed.
However, your starter may be fine, it needs some acid to ward off infection and stay healthy. Perhaps try a different bread making technique, like using the starter to mix bread earlier in the feed cycle (after it starts to rise but before it has fully risen and fallen back), and/or limiting the bulk fermentation.