I am on my second grow with the grobo. My first grow had the same issue, extending early and late veg for like an extra month and my plant still did not reach the second fan.
On this current grow I thought it could be temp issues, the room fluctuates between high 50’s to high 70’s from day to night but now I worry it may be a water issue.
I ususally have a brownish film on the underside of the lid (where the coco sits) during the weekly water change and 70% of the roots are browning. I use hydroguard with each water change.
So I am beginning to think the issue is a lack of water circulation due to the air pump being weak. I think a good fix would be to get an aux pump, split the output and put an airstone on either side of the stock air strip in the middle.
Any suggestions from the peanut gallery?
I can post some photos tomorrow when I do my weekly water change, and include any info that may help diagnose.
Suggestions on what size pump to buy and surface area of stones would be great, and where to keep the pump and run the lines.