Wtf is goin wrong

[Dosmokethereefa]

19l oxypot water circulated through a chiller set at 18° plenty of air being blown through, everythin goes fine until wk3/4 at which point the plant seems to stop growing new roots the oldest foliage goes yellow, then the finest roots drop off this is 3rd time in a row exact same symptoms any ideas be welccome?

 

[futurebanjo]

Are you monitoring your EC and PH?

 

[DanKiller]

Pictures man, your description is lacking, if all conditions are solid until week 3, no plant is supposed to suddenly die without appearnt reason...
Check what you are doing wrong, what parameters are you changing at that stage that might cause this drastic change, because it is drastic, from everything fine to dying is a long road that usually starts with grower error.
More descriptions of what actually the plant exhibits during that time of dying would be also beneficial.

 

[Hugo Phurst]

does it smell?

 

[Delps8]

18° is too cold for a res. At that temperature, you're getting a small amount more dissolved oxygen but P uptake is inhibited. Raise your chiller temp to 20°.


Check out this graphic. What are the readings?

Also, pictures help a lot.

 

[futurebanjo]

18° is too cold for a res. At that temperature, you're getting a small amount more dissolved oxygen but P uptake is inhibited. Raise your chiller temp to 20°.

You think?

My water chiller is set to 18, but in reality it rises to 19 before the chiller kicks in, and it turns off when it senses the water flow is down to 18.

So it's probably running 18.5 on average.

I'm not sure if that's a bit on the cold side, maybe I should set it to 19, so it will raise to 20 before the chiller kicks in?

 

[Delps8]

You think?

My water chiller is set to 18, but in reality it rises to 19 before the chiller kicks in, and it turns off when it senses the water flow is down to 18.

So it's probably running 18.5 on average.

I'm not sure if that's a bit on the cold side, maybe I should set it to 19, so it will raise to 20 before the chiller kicks in?

I'd bump it up to 19.

At 17.8/64, P uptake is/begins to be inhibited (I don't remember which is it). The increase in DO is minimal with a 1°C change but the possibility for decreased P uptake and, therefore, a nutrient imbalance, starts to increase. My chiller is set to 20/68 and the Bluelab reads 20 to a "skosh" under 21°.

It's a fine point but it is one more variable out of the equation so it will, in the long run, make things run better.