Super slow growth and browning roots- suggestions for air pumps to add?

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.

Mush love!


I would wait for feedback because these things are often subject to over thinking, although at this point there is definitely a probkem if you’ve been in early & late veg for 30 days apiece and haven’t made it to the second fan!
The brownish stuff around the coco pod is normal unless slimy/smelly, comes from nutrients!
Like before a month in early veg was when you should’ve start posting with pictures!
Early veg is not to be extended UNLESS you had trouble germinating and your plant is in shock/not growing.
Late veg is when you start to extend if needed.
Questions: Are you looking or exposing your roots to the light?
Using anything besides grobo nutrients & hydroguard?
How much hydroguard are you using?
Do you have fans on inside the grobo & where are they located.
Make sure to open the lid of the reservoir and take a picture of the water, roots, & sensors along with the nutrient bottles!

Pump I’m using currently, works great! I put one on each side of the resevoir and run lines out the back so pump sits outside the grobo for less heat issues! Found on amazon!

Uniclife Aquarium Air Pump Dual Outlet with Accessories for Up to 100 Gallon Tank

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I’m having the same problem with browning roots. I’m still in early vegetation and I used a battery powered fan inside the box (@ 1” away from plant). I add Hydroguard after every water change (@ 15ml.) and I have also stopped using the battery powered fan. This strain is Blue Dream and I have pics of the roots and the sensors on my profile.