I may be a bit off topic here but I use braided pvc for my sight tube. I only ever have veg oil in there...not bio...not meth...not WVO...but pure veg. With SVO it does not deteriorate.
I know this may only relate to volume in the reactor which is the reason for posting. I only put pure veg in the tube to tell me the level of wvo in the tank.
If you use the sight tube to give an indication of what's going on inside the reactor then you could be on a bit of a loser due to flow through the sight tube. IMHO..forget it!
Hmm, more than one way to skin a cat, Nige!
All depends on your valving arrangement, yours sounds rather restrictive. I can empty and refresh my sight tube whilst the processor is running. I use it to return samples to the processor frequently and, on occasions, to add water, acid and catalyst. I consider it one of the most useful components on my plant!
PVC sweats bio and goes translucent ... tried that. Acrylic crazes over time, goes brittle and slightly translucent. I'm going to give glass a try, may well be a better alternative ... unless we try new things we'll never progress!
I read it ... but I'm afraid "The future isn't always to be found in the past"!
