Mainline or not? Fairly new to tubing

[WMass713]

I have a question for the more knowledgable folks out there. I have a tubing run about 750' long with around 100 taps on it. Most of these taps are right at the line, however there are 5 spurs going off with anywhere from 5-15 taps on them, this worked great for the first year, however last season (2nd year) the flow seemed to back up in the line. This whole setup is run on standard 5/16 4-season tubing (the purple stuff) Different people have said that it's not the line size, others say we need to step up to at least 1/2" Mainline for the main run and feed it with spurs of 5/16 with no more than 30 taps on each. I have no clue where to start when it comes to mainlin, do I need it? Is the wire necessary or can it be tied off to trees like the 5/16? I would estimate that the total drop over the run is around 20 feet. Any advice would be greatly appreciated.

[Sunday Rock Maple]

3/4" main line on a wire. Lots of slope on the 5/16", keep them short and feed them directly into saddles with no "T's" or "Y's".

[WMass713]

Thanks for the advice, How short on the 5/16"? I ask because I have 2 spurs that have approx 10 taps each on them, but they need to run at least 50', however they have a greater than 1' per 1' drop for 3/4 of their length, in the interest of money saving I'd like to keep them run in 5/16" what's the difference in saddles vs Ts or Ys?

[Beans Maple]

You really don't need to use wire. Use 3/4" all the way and pull it tight with a good ratchet strap, then tie it from side in various spots along the run to further tighten and keep sags out of it. With no vacuum putting 15+/- taps on each lateral 5/16" line is fine. The saddles are the easiest way to get the 5/16" into the main. Are you leaving the line up year round or do you take it down?

[northwoods_forestry]

I'd go with wire and 3/4" mainline. You'll find the wire keeps the sags out over time which will be important with only 20' of drop. Use a wire ratchet and side ties to get the wire as tight as possible. 3/4" mainline instead of 1/2" allows you to use saddle fittings to enter your branch lines. If you are using gravity and not vacuume 30+/- taps per branch line with good slope is ok. Less than 10 taps per branch or poor slope will not allow for natural vacuume. You'll still get flow but it will be disappointing.

[WMass713]

Thanks Guys. One last question, is there a difference between main lines? ie Black, Clear etc? I do leave my line up year round and usually let it run a day or two to flush out naturally at the beginning of each season. Is this harmful? my 5/16" line is purple 4-season and has been up 2 years and looks new for the most part (besides squirrel chews)