plant leaves turning brown on the edges, also has spots on the leaves

[docholliday]

My plants are in the second or third week of flowering and started showing leaves turning yellow then brown on the edges. I thought it might be a pH problem, then some nutrient problem. (I'm growing with hydroponics the way Sirius Fourside detailed) This is also my first grow since the middle to late 70's. (I'm also pushing 70 yr. old; if that makes any difference) I've changed the nutrient solution several times to no results.There are also small white or yellow spots on the leaves. The problem has intensified in the last couple of days. Any help would be greatly appreciated. I'll try to send some pics once I figure out how to do that! The yellow of the HP sodium light makes seeing any problems difficult. I'm using a 600 watt HP sodium in a hydro grow with General Hydroponics Nutrient Trio with Hydroguard. It's in a Cool Grow 4'x4'x84" tent.

 

[alltatup]

Definitely need to see some pics, doc. I grow hydro; it sounds like you need to flush with pH'd water for 24 hours and then lower the nute solution a bit. It sounds like nute lockout to me.

My weekly regimen that seems to avoid nute lockout: Every week around 4 days after I've changed the reservoir, the water is low enough for me to add more pH'd water. Sometimes I have to do it twice a week (either they're drinking a lot or the dehumidifier is sucking moisture out of the reservoir!!) When I do this every week, it's almost like a mini-flush, and it keeps my girls chugging along.

 

[docholliday]

Thanks for the info alltatup, I'll do that tomorrow. I'll try to get some pics by then. I'm using a HPS and it's difficult to see anything clearly.

 

[alltatup]

If you really need to post pics for identification of problem, turn off the light for a minute; if we can't see the plant, we can't diagnose. ;-}