AeroFlo 30 - Foam in tubes and resivior

Hey all, I have am aeroflo 30 and as some of you know it is a bit stretched out for the one 600 watt light I have so I decided to modify it to 4 6 site tubes. All was a pain in the ass but I finally got it done and after 2 days of running my reservoir temp is 68 degrees, ppm is 1200-1400 and ph is 5.9. Temp is 75 during day and 65 at night with RH 45-50. 600 watt hps hydrofarm hood is about 10 inchs above the canaopy. Using general hydroponics flora nova 3 part system. What I noticed today though while rearranging the plants to get the best light is alot of foam has built up in the re and the end of the tubes. The tubes are set at the same pitch as they always been so the flow is good. However I did add 2 airstones to the reservoir . I am hoping it is not that big of a deal being the roots all still look fine and the foam is not smelly or oily or anything. I was wondering if anyone else has experienced this as I have searched and found mixed results. It just seems to me like oxygen is building up where the roots are restricting the water flow a bit. They are in 3 weeks of flowering. I should also mention I have changed some parts of the system including the reservoir, i changed the sprayers to 1/2 pvc with i think it is 1/16 holes pointing at 45 degree angle into the water but I cleaned and rinsed everything really well before hand. Everything looks healthy and the foam looks something like foam you would see on the beach after waves come in. The roots have a brown tinge but they are strong and not slimey so I am sure thats due to the nutrients. Here a couple quick pics i took of the plants. Tomorrow I am planning on taking some clones (I know I should have earlier but I want to clean up the bottom of them so might as well make them clones) and re-arrange them to get better light.

Also sorry for the crap quality of pics the lights just went out and I didnt want to mess with them much and if you see any brown leaves it is due to my old hood being to close to them for one day before I switched everything over...............anyway any opinions on the foam?? Would a picture of it help??