Ebb & Flow Flushing?

[Dirte Bag]

THE SCENARIO
VEG ROOM - 24 hrs of light
4 mothers in 5 gallon pots of soil under 8 4' T5's.
2 - 28 site cloners under 1 2' T12 plant light
1 - 16 pot ebb & flow table under 1 250w CFL using Growstone and Hydroton mixed 3 to 1 respectively

FLOWERING ROOM - 12hrs of light
1 - 4' x 8' ebb & flow table with 100 gallon reservoir with chiller (72°F) under 3 -1000w Eye Hortilux (2 HPS, 1 MH)
1 - 2'x 4' ebb & flow table with 40 gallon reservoir under 1 Kind600 LED
CO2 ENRICHMENT (1500ppm)
Dehumidifier (45-50%RH)
Mitsubishi Mini split (dedicated) 78°F
Atmospheric controlled
Reverse Osmosis water
General Hydroponics Flora Series nutrients

When 1' tall (about 2 weeks of weg) the 16 plants from the veg table (referred to from here on as "a batch") are moved to the 2x4 table, fed 3ml cal/mag and 5ml/gal base, grow, and bloom for 2 weeks then moved into the 4x8 table and fed 5ml base, 2ml grow, 8ml bloom, 3ml Kool bloom(liquid) and 3ml cal mag, changed every 2 weeks and topped off with RO in between.
The 2x4 table is then drained down to 3 gallons and filled back up with RO water where the oldest ,ripe batch from the 4x8 table are then flushed for a few days up to a week.
THE PROBLEM every batch starts having... problems right around week 6 of flowering.
First, the lamina between veins yellows, and then dies from the tip on the sativas. The margins of indicas curl up, eventually so severely they're almost tubes. In older plants the calyx tips die giving buds a thorny look. This was attributed to light burn but raising the lights didn't stop it.
Is this perhaps toxic salt buildup?! Should a flush be done every couple of reservoirs?
This is wreaking havoc with yields and appearance. HELP!

 

[Enforcer]

Having three 1000w lights over a 4x8 is more than likely your issue. You could adequately cover that space with only two of those lights.

 

[Dirte Bag]

Having three 1000w lights over a 4x8 is more than likely your issue. You could adequately cover that space with only two of those lights.

I initially had just 2 hps, and wasn't achieving the compact, dense buds these strains are purported to produce so I moved them apart and put the 1k mh in between to add blue. I also think I may have too much light.
What do you think would be "optimal" for a 4x8?

 

[jumpincactus]

I initially had just 2 hps, and wasn't achieving the compact, dense buds these strains are purported to produce so I moved them apart and put the 1k mh in between to add blue. I also think I may have too much light.
What do you think would be "optimal" for a 4x8?

He answered your question. 2 lights for that layout. Typically the thinking is more is better but in reality you can use too much light........

 

[Dirte Bag]

He answered your question. 2 lights for that layout. Typically the thinking is more is better but in reality you can use too much light........

I saw his reply and then asked another, different question. He said two would be adequate. He didn't say which two or that either are optimal. I'm aware of light burn/stress. Currently right around 28,000 lux at the closest plant top.

 

[Enforcer]

I saw his reply and then asked another, different question. He said two would be adequate. He didn't say which two or that either are optimal. I'm aware of light burn/stress. Currently right around 28,000 lux at the closest plant top.

In this situation, you could use adequate and optimal interchangeably. Two 1000w lights in a 4x8 is more than enough light. You could even use two 600w HPS lights and be just fine.