Opinions On Setup, Feeding, Possible Mild Nute Burn?

Hey everybody, first grow and I was looking for a few opinions on feeding schedule and whether this is a mild case of nute burn, or something else.

Feeding has been every 3 hrs for 3 mins every time. cubes will still be a little bit wet when the next feeding time comes around. I was also wondering if feeding at night is good or bad with my schedule. Currently they will be fed twice for 3mins during the 6hr dark period.

I have a few pics that aren't the best quality, but hopefully you can see the brown spots in some areas and distinguish the problem.

using dutchmaster gold A+B at 20ml/gallon PH adjusted ranges from 5.0-6.0
10ml h2o2/gallon
botanicare sweet grape at 10ml/gallon
temps range from 72-80deg
reservoir is around 70-72deg

The plants are more or less unknown, I got 4 different clones from a buddy and sadly only these two made it. I believe they are OG Kush and Bubba Kush, but I cannot be positive.



First picture is an attempt to show some of the brown spots. There are some spots underneath a few leaves as well.

Third picture I am trying to show a brownish/green area on top of the rockwool. I believe it is algae, and I have since covered the top of the cube with mylar hoping that will help.

Love to hear what you think, if you notice any problems, or have any suggestions or concerns.

Thanks

ya thats algee and ya thats burn, but it doesnt look like burn from within the plant... it looks like some nutes have splashed on the leaves and burned them from the outside... the tips of ur leaves would burn first if u were feeding them too strong

I was going to run an irrigation line out of a valve at first, but the line I bought was not the best option once I started poking holes in it... It had a bunch of fibres and such so I just ditched it. Instead, I just have a valve that shoots the water out parallel with the ground and fills it the tray very well. There is some splashing and some water/nutes do get on the leaves. If this is a problem I put a line on the end of the valve, but if its not much of a problem I would rather leave it as is.

Should I worry about the algae or just hope it goes away now that its covered? No light should take care of it, no?

should go away now that its covered... may wanna add some h2o2 in the res... that will kill it fo sho!

Thanks... H2o2 has been in reservoir for about 24 hrs now... If anybody wants to comment on the feeding schedule, or anything else that would be just swell.

I am using a similar setup with the rockwool surrounded by hydroclay and when my plants were that size I was feeding every 4 hours for 3 min. per time. When i first started, I found that I was overwatering but err on the side of caution and let it air out a bit. with rockwool, ive been told, it's almost impossible to overwater since it usually holds 18% air, but i'm no expert. i also had some algae issues, i ended up putting a towel over the top of my clear reservoir to keep the light from shining on the water. problem solved.