I'm still waiting for the Canna Nutes (should be here this week) but the addition of the un-softened tap water has done the trick. A few days after adding it several fresh, spot-free green leaves started growing. The plants are now flourishing.

The water here measures 1250 ppm out of the tap and is loaded with Ca++ and Mg++. Nasty to drink though...

Thanks for the advice everyone!
cosmas Reviewed by cosmas on . Help! I'm almost out of weed and the leaves on my resupply grow look like this! I've had this problem since nearly the beginning of the grow and can't seem to get it worked out - I'm in week 5-6 of veg and it's getting worse. Lower leaves seem to be more affected than upper. I'm growing white widow from seed in a dwc/bubbler setup (good airstones and pumps) 1.5 " rockwool cubes (now dry) in meshpots with clay pellets Distilled water, changed every 1-2 weeks, nutes at 500 ppm temps max at low-mid 80s daytime and min in the high 60s-70ish at nighttime. 230 watt HPS Rating: 5