the roots are brown and rotten

[GpsFrontier]

First I need to know witch of the six type of systems (or combination of) you are using.

1.drip system
2. Ebb-Flow
3. NFT
4. Water Culture
5. aeroponics
6. Wick System

I understand that you have been having the same problem for a while. Are tomatoes what you are trying to grow or does it not seem to matter, and you been having this problem no mater what you were trying to grow?

i use blue lab truncheons

If I understand correctly these are pH test strips?

they show sighns of roots onto the spreader matt, then the rockwool blocks get completley soaked, and the roots turn brown

I am not sure what the spreader matt is for but the type of system may help explain that. Can you give me a link to what spreader matts you ate using?

i have tried leaving the pump off to dry them out a bit but to no avail
and they end up dead,

how fast are you talking about here, minutes, hours or days?

there tomatoes, and i was at 5.8 PH

this probably could be a little higher for tomatoes although 5.8 is is within there range.

nutes at 1.4 or 14 depending on what scale your using

I assume you are talking about PPM here, and for tomatoes that is at the low end of the range at 1400-3500. Though as I said before I don't even own a PPM or TDS meter, so I cant even check it for my plants but have not had a problem there yet.

and the roots turn brown, then the plants just droop as if there overwatered, then the leaves go yellow verry quickly,

I have an idea that the nutrient temp is too high because I have had the same problem here before. The nutrient temp for all plants should be between 68-72 degrees. If it is not cool to the touch it's way too high. Also any flowers will turn yellow and fall off as a survival instinct.

I am assuming that you are using commercially made hydroponic nutrients? I am only familiar with one type but if you have a link to what you are using it may help. I also am not sure what your growing environment is like, heat, humidity and lighting, all can be factors. If you have any pictures of the system it would help. I am sure we can get it figured out. I am no expert in hydroponics but I love to help anyone I can.