My Hydro plants aren't doing too well

[Chen]

It's a simple DWC setup. Reservoir pumps water through PVC pipes.

Everything was going well until the summer came in and I started using the AC, but I can't see any reason why that would have affected anything since temps are good. 25C all around and 26C in the reservoir.

I feed them Lucas formula just as always. pH 5.8. 600w HPS.

It's always been a fool-proof system, so I'm wondering what the issue could be.

Appreciate the help!

 

[pcduck]

Rez is to warm. What does your roots look like?

 

[RubyRed]

Dam that's Ugly Yo

 

[Surfer Joe]

Check the roots and the rez temps.

 

[Chen]

I have two reservoirs. The res temp is ~26C but the water goes all through a system of pipes, which I assume cools it down. Is that really the only issue?

 

[Surfer Joe]

I think the rez temp is too high and should be closer to 18-20C

 

[Hushpuppy]

Oh man if I translate that correctly, your rez temp is 76-78f??? That is waaaaaay tooo warm. Your water for plants should stay between 65f-70f. about 18-21c like Joe said. I had this very same problem with my last run. I couldn't keep the rez cool enough, even using 2ltr bottles of frozen water, couldn't keep it cool enough. I got a bad case of Pythium (root rot). That may be what you have going on, or it could be bugs as it looks like thrip attack on the leaves with the spots. But even if it is thrips, that rez MUST be kept cooler. I had to buy a 1/10hp chiller to keep my rez cool. Now it stays right in the 65-70f range constantly. They are a bit expensive but they are totally worth having if you run hydro.

 

[Chen]

So, if I'm getting this right.. you're saying water temp could be the single cause of this? Why is it so important?

 

[Hushpuppy]

At this point that is possible. Water holds dissolved oxygen best at temps between 65f-71f. This oxygen is critical to root health. You can keep plants floating in water as long as the water stays at right temp and is well oxygenated. At temps as high as you have, there is very little dissolved oxygen as the water is unable to hold it chemically.
The other problem with the warm water is it allows pathogens access to the plants roots.

 

[The Hemp Goddess]

A few years ago, I started doing soil for summer grows. I love hydro, but it was just too hard to keep the res solution cool enough with summer temps.

 

[Hushpuppy]

Unless you have a recirculating system with an external reservoir, its hard to keep em cool. I have a hard time keeping my seedlings and cuttings cool when they are in the solo cups. Im thinking about wrapping them in aluminum foil to keep the radiant heat out of the medium, or would that bake them like potatoes

 

[pcduck]

Like a potato.

 

[Chen]

Alright, well what I did was I positioned the AC ducts to run through the reservoir.

The water temps are somewhere between 20-22C. So far, not too much has changed but I'm hopeful..