sleepydoc
Team RC
The John Guest fittings are made for polyethylene tubing, similar to what probably came with your RO filter.
For startrup, when first adjusting the system, you'll see bubbles coming out of the siphon channel until all the air is purged, at which point it is a true siphon. If there are bubbles coming out of the open channel at this point then you have too much water running through the open channel; open up the siphon valve slightly and let it settle again.
Definitely get a gate valve. Even with a good quality ball valve it will be hard to fine tune it properly.
To follow up on your question regarding the sanitary Tee, as Rybren said, sanitary Tees have a sweep. Bean used a sanitary tee thinking it would reduce turbulence. Sanitary tees DWV fittings and not available in 1" sizes. 1.25" sanitary tees are technically available but are very difficult to find. People have used regular Tees without issue.
For startrup, when first adjusting the system, you'll see bubbles coming out of the siphon channel until all the air is purged, at which point it is a true siphon. If there are bubbles coming out of the open channel at this point then you have too much water running through the open channel; open up the siphon valve slightly and let it settle again.
Definitely get a gate valve. Even with a good quality ball valve it will be hard to fine tune it properly.
To follow up on your question regarding the sanitary Tee, as Rybren said, sanitary Tees have a sweep. Bean used a sanitary tee thinking it would reduce turbulence. Sanitary tees DWV fittings and not available in 1" sizes. 1.25" sanitary tees are technically available but are very difficult to find. People have used regular Tees without issue.