Cukes are hard to grow in Hydro. They do not like getting their feet wet. Some suggestions, aerate the hell out of the water, and cut back even more on nutes.
MGM if you would like let me know I have a book in my collection that's prett advanced on hydro .. Hydro for the soilless grower by J Benton Jones Jr outstanding book I musy say ... Let me know if you would like my help it has a section dedicated to about a dozen crops that work well in hydro along with tomatoes cukes and peppers. I can give you the formulated range tolerances for nutrient formulations and nutrient deficiencies ... Just post up and I would be more than glad to help ..
MGM I tried posting wed morning and something was gliching with this page anyway e mail me if you want forgive my entry but I'm trying to tip toe around watching eyes and spammers ... Anyway its. b r i a n 0 4 1 4 8 2 @ hot sorry didn't wanna make it so obviouse but again more than happy to help if you need it just hit me up