That does tend to happen when making Colloidal Silver . There are methods to reduce or prevent it. One is to switch the polarity so that the current flows in different directions which helps prevent the deposits on the electrodes. This would need to be implemented in the generator design but might be possible with a separate circuit using a relay and timing circuit. The other method which I have seen is to add sodium carbonate to the water which prevents it from happening. Unfortunately when I tried this it affected the voltage, dramatically lowering it. The recommendation that I got from the person who recommends this on the forum linked below was to raise one or both electrodes or separate them I cannot remember exactly what he recommended because it has been quite some time ago. The generator that he sells does not switch polarity BTW which is why he does it the way that he does with the sodium carbonate. For me switching polarity was the best option. https://www.cgcsforum.org/
You need to prevent any of the deposits dropping into the water. It will do that if it is allowed to build up too much. As to the colour change, you might be having the process going on too long because the colour does change the longer it goes on. That can degrade the quality. It might be worth measuring the currrent going through it to check that the current is being regulated correctly. There is a relationship between the silver electrode area and the current and the current should be kept at the correct level for the electrode area.