I am using 37g rubbermade totes with 4 girls in net pots full of jumbo perlite. They come out of the cloner with beautiful white roots and when introduced to flower dwc they get algae/root rot. 5.5 pH 400-1400ppm 64-68F rez temp. Had 1 group that didn't get it until I did a nute change after 3 weeks. As soon as I changed out it started in that tub too. I use uv/ro and treat with physan 20 with light proofed tubs. I use hygenic practices and am very careful about contamination. I have gone back to some soiless pots because of the disapointing yield. Is there a secret that I'm missing? No problem with pots, no problem with fresh/salt water aquariums...BIG prob with dwc...WTF. Wilting plants with brown/black roots kill my buzz. Any inteligent help would be much apreciated.

Boy, I dunno doc. I would say a hot rez but not at those temps. I Liquid Karma will turn roots a brown kinda color, but no ill affects to the plant. Got a pic of your set-up?? Not much help huh..

How much air are you delivering to the tubs? (Amount of airstones, amount of pump outlets running the stones, etc)

Also, how far are you filling the totes with nutrient solution? How much root mass do you have above solution and how much is in it?

Consider using some H202.
Rootbounds got the right idea also. No Oxygen will do that to a plant.

Yeah, krimzon saw where I was going with that one and spoiled the ending. Lol.

But yeah, if you aren't delivering enough oxygen to the roots you are basically drowning them and they will start to brown and die rather rapidly. It's basically the hydro equivalent of overwatering in soil.

I though o2 also, but I have a gigantic air pump with very efficient stones like 18" around. I have been using foggers in my tubs also. I have varied the water level from touching the bottom of the pots to 9" air gap. The tub that went 3 weeks without change had a recirculating pump in it...so that's when I thought o2, but then I did a rez change and within a week brown roots. 70/30 roots in air/water. The brown starts at the air/water level. No h2o2 used yet. Thought it could be done without using h2o2...maybe not. I appreciate you guys input and hope we can sort this out. I was sooo impressed by the growth when healthy, but....you know. PS. I have pictures on photobucket and have know idea how to get them here...so .....If I figure it out you'll know

[img][IMG]http://i1178.photobucket.com/albums/x367/larryisdumb/DSCN0736-1.jpg[/img][/img] These girls are 58days in flower and are NOT a dwarf indica strain. HOLY SHIT I did it. Pictures....this is my 1st ever posted picture. WOWEEE! OK now you kind soldiers can really see my torment...and perhaps unlock the secret.

[img]http://[IMG]http://i1178.photobucket.com/albums/x367/larryisdumb/sick%20shit/DSCN0733-Copy-Copy.jpg[/img][/img] [img]http://[IMG]http://i1178.photobucket.com/albums/x367/larryisdumb/sick%20shit/DSCN0734.jpg[/img][/img] [img]http://[IMG]http://i1178.photobucket.com/albums/x367/larryisdumb/sick%20shit/DSCN0716-Copy-Copy.jpg[/img][/img] [img]http://[IMG]http://i1178.photobucket.com/albums/x367/larryisdumb/sick%20shit/DSCN0726-Copy.jpg[/img][/img] [img]http://[IMG]http://i1178.photobucket.com/albums/x367/larryisdumb/sick%20shit/DSCN0717-Copy.jpg[/img][/img] [img]http://[IMG]http://i1178.photobucket.com/albums/x367/larryisdumb/sick%20shit/DSCN0726-Copy-Copy.jpg[/img][/img] [img]http://[IMG]http://i1178.photobucket.com/albums/x367/larryisdumb/sick%20shit/DSCN0730-Copy-Copy.jpg[/img][/img] [img]http://[IMG]http://i1178.photobucket.com/albums/x367/larryisdumb/sick%20shit/DSCN0729-Copy.jpg[/img][/img] I hope this is apropriate...it looks creepy to me

[img]http://[IMG]http://i1178.photobucket.com/albums/x367/larryisdumb/DSCN0664-Copy.jpg[/img][/img] This is the mom for those pygmies. Over 5' [img]http://[IMG]http://i1178.photobucket.com/albums/x367/larryisdumb/DSCN0669-Copy.jpg[/img][/img] and a bud shot for good measure....any other pics you guy need let me know since I have a new skill to practice.......Look text and pics together......snazzy eh?

After looking at your pictures, I definately believe you have your res level to high. If you hold your hand directly over the water you can feel the water that is being misted up by the popping bubbles at the top. That is more than enough to keep the roots moist while they hang in the air. I would drop the res level some if I were you.

That being said however, I don't think that is your problem. What is that physan 20 you are talking about treating your water with?.... Why are you treating it at all if it is ro?.... And, did you clean the tubs before the grow?... If you did, with what?... And are you absolutely possitive you rinsed it ALL out?