CITRIC ACID WASH. Once in a while you need to put a citric acid wash through your condenser. This is especially important if you have noticed your temperature being erratic for no reason. Use a pump to push 1l of water with a 100g of citric acid in it through your condenser for about an hour. You may already have a water regulating pump to keep your temp stable when distilling, if not have a look at the still spirits water flow regulator https://thebrewshed.com.au/product/water-flow-regulator/.
The picture below is what came out of ours, we are on tank water https://thebrewshed.com.au/product/citric-acid-cleaner-1kg/