Thanks for your insight. So, what you are saying is a thin slimy layer on the hoses is normal. Some clarifications and some answers: The drum is light proof, take my word for it. The black plastic covering, i meant the opening in the drum through which you get access to the inside, put
pump in and so on, is covered with plastic. The pump is run at night. I had run the system to make a video just before I took those pictures, that is why you see water. I had graded the inside of the box so well, not even a drop of water hangs around after it is drained. There is absolutely no green algae in the box or hoses or the drum.
The Bell Siphon is covered with a filter. so no extraneous stuff goes into the
nutrient. Believe it or not, there is not much debris or critters in the filter or in the box. I emptied it out today and it is very clean.
I might have misquoted somewhere, the system is 4 weeks old not 4 months and yes, i did not change nutrient yet, but i compensated by a lot of volume to begin with. The volume needed to flood is only about 3 gallons and I started with 20 gallons.
As I said I am moving plants out of this into different system. I will update on that later. Thanks.