Maybe I can share some experiences about ulva, it seems the keypoint for ulva is the current, not the temperature, light and nutrition:
Last year, one of my friends try to DIY a ATS system, and complete it with an old small cube, his ATS has a bucket mount on the top of the tank, and keep a small refugium area on the bottom of the tank with some live rock and algaes, and some rocks with ulva we collected from north Chinese sea.
few weeks later, we noticed the ulva begin to grow in the refugium area, then the ulva begin to grow crazy(must be harvest every week), at last, almost every kind of algaes could not compete with ulva and they have disappeared, the photo is as following:
With ulva rapidly grow, the nitrate has droped fast, from 25ppm to 0ppm in just few week, and phosphate also droped to 0ppm. (with Salifert test kit)
When the nitrate becomes zero, the growth rate of ulva is slow down, and the other algaes could not survive even the turf on the ATS screen.
We all shocked with this and try to find out what is the key point for ulva growth, we have try to put the ulva into the sump of the same tank, the screen of ATS, but all failed, it seems the ulva could only be thriftily in the refugium area of ATS tank.
So we think the current is the key point for the ulva growth in aquarium, the best stream for ulva is the current back and forth just like current at coast. The current maked with ATS bucket helped ulva to grow.
Now we have do more test with ulva and it seems the stream by the pump also could help ulva to grow, but it is not as good as ATS bucket does. (I think the TUNZE wavebox is good choice for ulva but it is too expensive

)
We are still doing some dedicated test to find out if the current is the keypoint and what could make ulva grow fast in the aquarium, we think the ulva is a good choice for the reef tank to keep the nutrition low, with ulva's great contribution, the color of my friends' SPS looks great then before and he have many fishs in this tank:
sorry for the lengthy text and my english is not so good, I hope it could be helpful.