dieing plants brown roots

[the big purple]

hi guys ,ive been having this prob a while now,i use nft till plants are big enough with healthy roots then into a bubbler .my problem is whenever nice thick white roots show through the rockwool they turn brown and the plants die.i dont think its rot at first but then after days of not feeding they begin too rot.i dont think its root rot as ive used h2o2 and pythoff,but no joy.a few of the dieing plants from the nft grew no problem when i ripped all the dead roots off and replanted them in soil.
i have grown this way for 5 yers or so with no probs but stopped for a few months and now everything i do fails.any ideas

 

[ItsGrowTime]

What's the water temp in your bubbler and/or NFT? Anything about 75 with no treatments will start root rot.

 

[the big purple]

hi mate thanks for ur reply the water temps are usually 65 and never higher than 69.can u tell from the pic wether it is root rot???my plastic tent temps are quite high at 75-85,could this be the problem???i have now added extraction so hopefully room temps will be lower when i check later

 

[ItsGrowTime]

It doesnt look like root rot to me. And with those water temps it definitely should not be. You're right, they don't look good though. Doesn't look like algae either. Strange. Hope you get it sorted. Hopefully someone else can speak up if they have an idea.

 

[BigAl]

It looks like root rot to me.

Your reservoir may be sitting at 65 but what temp do the growool slabs reach between watering??

I have two suggestions, the first is to water more often and the second is to use slabs that are covered in plastic.

I read all over the place that you should only water growool slabs in an ebb and flow system like 4 times in a light period but this is wrong. Ebb and flow systems in rockwool can be watered 15min in every hour no problems, you can even push it to 15min on 15min off no worries. Try and you will see!

Same rules apply here as they do with DWC. Rockwool slabs are not lightproof, limiting light penetration will benefit the rootzone. The channels in your tray should be crammed full of white roots.

Now for the good news, you can still yeild a big crop from plants with a shitty rootzone.

 

[Suby]

That looks like rot to me, take a root and roll it gently between your fingers, if the root mushes between your fingers leaving only a fine strand of root then it RR.

BigAl made a good catch, your res might be 65 but once the cubes are left to sit that water in the cube will rise to ambient temps unless you have something to keep them covered.

Cab temps of 85 are high, in my setup temps like that lead to rot every time, the spores are all over so as soon as conditions are right it will come back.

 

[ItsGrowTime]

BigAl made a good catch, your res might be 65 but once the cubes are left to sit that water in the cube will rise to ambient temps unless you have something to keep them covered.

That definitely is a good catch. Makes sense.

 

[the big purple]

thanks guys,i will check the temps of the rockwool