Given that algae is really harmless to plants, I only treat with H2O2.

Algae competes for nutrient with the plant but is not pathogenic. The green growth is an aesthetic problem.

Aside from the aesthetic issue here are a few more:

1. Economic. H202 cost about $2/liter and I use about 0.5 liter/week. So the price to keep my buckets algae free is costing me around $50/yr.

2. Algae consume nutrients and oxygen from solution that the plant needs. Why give algae free room and board.

3. When algae die they deplete oxygen from the water leaving less for the plant.

4. Algae can thoroughly coat the roots of plants that hang in solution cutting down on root efficiency.

Some additional random thoughts on using ultrasonics for algae control.

1. I'm guessing only a one-minute exposure is sufficient to keep the algae down in a five-gallon bucket.

2. Excessive ultrasonic exposure may be damaging to roots suspended in the solution.

3. Mosquito larvae may or may not be controlled by ultrasonics.

You can also get a 35% food grade H202 if you don't want to buy a bunch of 3% pharmacy stock bottles. It last much longer do to its concentration. I also use it in my hot tub.

I sorry to report that (at least in my experiment) algae control with the use of an ultrasonic fogger is not preventing algae growth.

Image: Full view of fog cloner

Image: Close up of algae growth

I darkened and contrasted the image in order to show the green-yellow algae growth on the bottom of the container.

Well, back to H2O2.

"If we don't succeed, we run the risk of failure".
Dan Quayle (1947 - )

Do you think if you darkened your tank it might work (along with your anti-algae system)? Have you noticed whether your ultrasonic irradiation device delayed the onset of algae?

I think you commented on another post that those in areas with a higher light intensity may have more problems. I have noticed some of the growers who seem to cringe with algae problems are from the high sun intensity areas. I agree we need to try different things. The 30 percent peroxide idea is good, but in reality, there may still be problems.

The sun in my area gets so intense I built my greenhouse with panels to filter out the light. My plants will burn otherwise, & some of my roof panels have burned from the sun. I still have algae problems, despite all the precautions, & like you, I am still experimenting. I am getting algae in my NFT & flood & drain systems. I am experimenting with bubblers & various rocks, however, using a commercial air pump. I have been so busy & have just stuck the air hose in the bubblers. I have not seen algae in the bubblers, despite 3 months of use. I have not covered the rocks or nutrient  they are exposed to light. I have seldom used peroxide in the bubblers.

Hi Baci

I deliberately left the cloner near an area where I get direct sunlight for one hour each day (if it's not cloudy or raining that is) just to see if constant ultrasonic exposure would keep algae from growing. The appearance of algae took five days. Needless to say I'm disappointed in the results.

Today I put one fluid ounce of 3% H2O2 in the solution and half hour later the algae were gone. Only little brown particles were left. Perhaps the ultrasonic exposure helps the H2O2 in some way kill the algae because they went very fast.

Maybe the intensity or frequency needs to be different for this technique to work. Unfortunately I don't have the equipment to experiment with these two variables.

Your bubbler comments got my wheels a crankin.... :-)

Hank

You could always see if the ultrasonic irradiation delayed the onset of your algae or if it disappeared quicker with the peroxide (after the irradiation) treatment. If it did, & it was cost effective, maybe the two could be used in conjunction with each other.

My air pump cost about $60.00, & supposedly feeds 16 tanks. I am running about 8 on it; which seems to be its capacity. I also saw some 30% peroxide the other day for $10.00/quart  I do not know how much that would add up during a year. Anyway, I will see how it does throughout the summer. My NFT system has developed algae, but I am using a smaller air pump on it. I will switch to the larger pump & see if that helps.

Baci, estimate the amount of H2O2 (qt.) you would use in a week's time, multiply that by 54 then multiply that by $10/qt. That should give you an estimated cost per year.

Seems like your bubbler does two things. One, it maximizes O2 (DO) in the water and two, water is put into motion. Maybe the water movement is keeping the BG algae from sticking to the surface of your reservoir walls or plant roots. Not sure about the relation between DO (dissolved oxygen) and algae growth however. Need to do more research.

I'm thinking of adding a small bubbler to my fog cloner. Going to cut off the H2O2 and try again.

Well, I added a bubbler to my fog cloner and after a week no signs of algae. Need to watch it for another week or two.

One thing I noticed about this setup is that the ultrasonic unit heats up the water, maybe excessively. I don't have a temp sensor or thermometer but I think the water temperature is close to 85 - 90 degrees. I'm sure this is not helping the lettuce seedlings because they look thin and weak.

At this point I'm not that impressed with fog cloning. I can always remove the ultrasonic fogger add more water and turn this in to a POB (plain old bubbler).

:-)

The heat produced from the fogger might be a definite advantage with fall cloning. You could add ice to your tank or put it in the shade to see if it perks up the lettuce. I would think the combination of the fogger & bubbler would increase the oxygen supply more than one alone.
As it heats up more, I am starting to see some algae in some of my bubblers  mainly the white ones or those that are not opaque.

I have an ultrasonic cloner I built last year.

The ultrasonics don't kill algae that I can tell. Perhaps with a LOT more power than one mister.

In my seed flats under lights in the basement, algae was building up.

I found that a spray bottle with a solution of strong chamomile tea and just a tablespoon of peroxide kills algae quite well.

Seems like I have algae problems now... i need help in eliminating it. I don't have the ultrasonic fogger (heck i don't even know what it is hehe)

I have an ebb and flow system for my "nursery" that i constructed from styrofoam tuna box. It's pretty sunny here in the Philippines and i put it on the roof. After 2 weeks i notice that algae has grown everywhere from the medium to the roots of my "taiwan hybrid pai-chai".

I heard mention of using hydrogen peroxide. How do i use it and in what concentration? Do i spray it or dilute it into the nutrient solution?

Perhaps what you read was Ultraviolet irradiation, UV systems are common in ponds and high end fishtanks and they kill anything in the watercolumn, Fogger disks however produce no radiation (they have impact waves with radiate but thats a different story). So, google UV filter, useually they are canisters that hoouse a UV lamp in a quartz sleave and direct the water around it in a spiraling fashion.

Hope this helps

Hi Brendan

The algae control using ultrasonics came from this site.

http://www.sonicsolutionsllc.com/product.asp

It's quite clear that the 6 watt fogger I used was inadequate for the job.