water chemistry questions for hydro

I need a water/plant chemist to help me with the following starter numbers -

pH 8.0
TDS 600-700
dKH (Total Alkalnity) 7.4
Phosphates 0.5
Nitrates >100
room is a bit too hot and "enclosed" and gets to 90 degrees with 18 hours of 2x1000 Watts light

On 3/7 I started a hydroponic grow with 24 plants, I lost half of them in the first 2-3 weeks.

about half of the remaining were severely "stunted" or "failed to thrive" over the next 6 weeks

10 weeks into the grow I had to leave for a week and lost a few more, I left them pretty much alone for 8 days

At 12 weeks I moved to 12/12 and "Bloom" nutes at 100 ppm, and the rest of my plants are turning yellow and dying, I'm pretty damn sure I'm going to lose 24 clones in this grow.

I posted some pix here at one point
https://www.rollitup.org/newbie-central/312118-yellowing-leaves-hydro-setup.html

I try to lower the pH to 5.5 - 6.0 but my pH bounces around pretty intensely, I'm really having a hard time keeping it in a range the well water starts off at 8.0 and 600-700ppm

The well is very near a golf course and I wondered about fertilizer / weed killer runoff

In week 2 I added FloraNova Grow 100 ppm
at week 3 another 100 ppm
at week 4 another 200 ppm
at week 6 another 200 ppm

When I moved to the "FloraNova Bloom" and 12/12 lighting I backed off the nutes to 100 ppm

Any ideas what's gone wrong?

Right off the bat I can tell you that your pH is way too high for hydro. I'd get a reverse osmosis filter if I were you to control what you're getting in your water. Also, as you add pH up and down to the mix, it will buffer the solution and stabilize, so keep with it!

Your growing in an ebb and grow.

If your room gets to 90 degrees then your reservoir is getting close to that as well. Your also using an organic mix fert which doesn't bode well at those temps in this system. Im surprised your not bacteria ridden and starting to get root rot.

You should...
get an RO unit or use a different water source because yours is very hard.
get those temps in the room and in the reservoir under control
Use chemical ferts and bleach in that system.

Man, how did I read that post and miss the part about the temp being 90 degrees? Yeah, that too

JeffersonBud said:

Your growing in an ebb and grow.

If your room gets to 90 degrees then your reservoir is getting close to that as well. Your also using an organic mix fert which doesn't bode well at those temps in this system. Im surprised your not bacteria ridden and starting to get root rot.

You should...
get an RO unit or use a different water source because yours is very hard.
get those temps in the room and in the reservoir under control
Use chemical ferts and bleach in that system.

Click to expand...

I will be using RO water.

What "chemical ferts"?

any suggestions on cooling the room it is a basement room with no windows?