What to do about algae

I’m new, and I mean brand new to the hydro method. I currently have 4 plants under a 600w HPS, in a 4’ X 4’ tub designed for about 16 - 20 plants. (I plan to expand when I know what I’m doing), Anyway, I have good water, re-circ pump, and I am using “Cultured Solutions” nutrients. I’m 9 days into the grow, have roots starting to appear from holes in pots. I monitor pH and PPM almost hourly, but the problem is that my water is starting to look like St. Patty’s Day beer in Chicago. I have done the Hydrogen peroxide additive minimally out of fear that excess would be destructive. The leaf growth is phenomenal, but what do I do about the Algae? Please help. Thanks.

Lower res temps to 67-69 degrees and hydroguard is a good solution as well.

Using hydrogen peroxide 1/2 tsp per gallon, but you only use one or the other not both


@Karma I’m still on my first hydro grow, but if it was me I would change the reservoir water asap. Get an aquarium thermometer and check res temp before you change the water. If temp is above 73-74 degrees, I would try the 3% peroxide at 10 cc/gal. If below that, hydroguard may be best. I have needed peroxide in my buckets cuz my water temps have been 78-80. (I did finally save enough for a small grow room AC this week) Also, if your temps are high, you will need an air pump on steroids to keep o2 levels up, plus as peroxide degrades, it will add o2 into water.

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First of all, thank you for the timely reply. My temps have been running between 72 & 75. I did not know about the Hydroguard. Will check that out. Wish me luck.

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Thank you Bryan for your timely reply. My temps have been running between 72 & 75. I did not know about the Hydroguard. Will check that out and lower temps. I just fed them nutrients this AM so I will let them soak up a little food before changing out the water. pH and PPM are w/in range and foliage is good, so nothing is life threatening at the moment. Thank you again. Good info.

My pleasure keep me updated

It appears that you are allowing light to penetrate your reservoir. This unit is for growing herbs or lettuce etc…

Make your reservoir light tight where no light can hit the water, and once you clean up the current mess; You will be fine Happy growing:)

Thank you for your reply. I did have the area covered but it was not light-tight. There were small gaps between the pots. I thought with the water circulating as steadily as I have it, that would suffice. Apparently not. So, will make the correction and thanks again.