I think you are confused by saying @7 ppm . Do you mean EC is 7 ms/cm-1?,if so, your nutes is very concentrated and should not exceed 2.00 ms/cm-1.
Make the nutes again, adjust the ph,and measure accurately the electrical conductivity "EC", the most important is the EC not the tds in ppm.
I am not familiar with GH fn grow? is it designed for Hydroponics?, if so,it should be a complete nutrients to support plant growth. Pleses let me know the ingredients and percentages of all nutrients in GH fn grow.

well its close to 1.8 ec sorry i dont have a meter yet to take ec reading just a oakton thats does ppm i cant say the name of the nutes some reson they will not let me do it saying i am spaming but yes its for hyrdos GH flora nova one part here what in it its a one part 7 4 10 plant food made for hydro stystems
0.9 % ammoniacal nitrogen
6.1% nitrate nitrogen
4.0% phosphate p2o5
10.0% soluble potash
4.0% calcium
1.5% magnesium
2.0% sulfur
0.1% chelated iron

i all so got GHflora 3 part series and other addatives

It seems that you are using a good formula for vagetative growth. The problem you have could be due to salt accumulation in your growing medium, it is recommended to flush the system throughly with pure water every week or two before adding a new nutrient solution to get rid of any salt accumulation.
Of course giving the plnts the proper light, watering properly, good ventelation and the right temperature.
Another explanation for your problem is due to an excess of chlorine in the water supply. I would discard these plants and start all over.
After the plants grow well and start to reach the blooming phase, usually 6 weeks after transplanting the tomato plants, you can switch to Flora Nova Bloom.
Good luck in your experiment and let us know how things are going.

Horticulturist,
S.Z.

Thank you SAFWAT i just starting flushing will add flora nova bloom and some GH floraciouius bloom i was thinking could it be i am not flooding anought i flood twice a day and just let it run back to the rez. i took a made 3 clones of her put 2 out side there doing great in soil got 30 tomatoes growing on the 2. the one inside i placed in a 1 gallon coffee can and made a bubbler now she is going a lot better. the one in the flood and drain is getting worse now the hole steam is dying from the tips and a lot of the leafts are truning brown from the tips same with the flowers. and they get a few hours a day of son light but the clone is all so getting 4 more hours of light with a 25 watt clf. and what is up with this site i cant say what nutes i use ummmmmmmmm not a good thing.

my tomatoes are healthy and full of blooms but they fall off and not tomatoes.

I am having the same problem. my leafs are browning at the tips. My Ph levels are at 6.0-6.5 I have the right amount of nutrient solution in. I am also changing the water every two weeks. Grow lights. and the temp is at 77 most of the day and night. any ideas

I'd love to know this too.

Mine aren't there yet (getting ready to move stuff up to other pots) but I'd love to know what I'm going to run into.

I'm changing the res every 2 weeks - using spag/perlite/ver mediums. . .peat pots. . .hoping to not have to pull anything apart, just up them to larger pots. .

Just as a question. . . do you have a really good air stone in your system? Just for info sake, I have to tell you, those 4" round ones are really getting on my nerves.

The long blue stone seems to be wonderful for spreading out the air, and doesn't have floating problems. It's heavy enough to lay on the bottom without any issues and spreads the air out. I may go and get more of those rather than these annoying round ones.