Thaumcraft, making aura nodes bigger.

[Azurl]

I have a small problem with my method of making the aura node near my laboratory grow. I had a node with max aura of 136. sometimes it grows by a tiny amount, sometimes it instead shrinks, it's currently down to 126.
I keep planting the silverwood trees in a line close to the node, I guess they all merge into that node since there are at most 2 nodes in that area at any given time. but why does it get smaller??

 

[id_missing]

I was growing a node today, got it up to 300+
I found the best way for me was to plant 2 saplings roughly 15 blocks apart, 7-10 seems to be the limit for attraction between nodes.
Once they had both grown, and had full vis, plant a third in the middle of the two. All three will then form 1 node.

Just be careful of the massive amount of flux that can generate during this process.
By the time I was done with mine I had high flux that took quite a while to get back to minimal.