Algae control in rain barrel

Hobart, IN

I hope this is the right forum for this question. I installed my first home-built rain barrel last year. The small amount of water that remained in the barrel over winter has some pretty interesting algae growth. I haven't yet hooked up the rain barrel for this year because I'm wondering how to control the algae growth. Does anyone have any "safe" recommendations? TIA

So.App.Mtns., United States(Zone 5b)

Cindy, you have the kind of problem that folks with ponds probably know about. You might try posting on this forum:

Paris, IL(Zone 6a)

Several weeks ago I was reading a web page regarding algae in a rain barrel. Most of the responses on the page didn't consider algae to be a bad thing. More problems were created trying to get rid of it (or not get it) than the algae caused by being there. I was almost convinced not to worry about it until I remembered the reason why one doesn't want algae in a rain barrel. It clogs the spigot making it difficult/impossible to close the valve that keeps water in the barrel. A rain barrel that doesn't hold water is like not having a rain barrel.

All one needed to do was add two ounces of bleach when the barrel was nearly empty and ready to be re-filled. The next rain will dilute the chlorine after it's had time to stop algae growth. Never leave water in a barrel longer than a week (5 to 7 days). If it has been 4 days since the last rain and more rain is expected overnight then empty the barrel. Fresh water doesn't grow algae. Only stagnant water does.

Clean out last year's barrel. Make sure you get the "interesting growth" out of it. Rinse it a time or three. Set it up to collect rain water after pouring in a couple ounces of bleach. It should be good to go. DON'T LET WATER STAND IN IT NEXT WINTER. Turn it upside down for storage if you can.

Deep East Texas, TX(Zone 8a)

Actually what causes algae growth is sunlight. If you have it sealed to the sunlight, as in a dark barrel and lid you should not have an algae problem.

Paris, IL(Zone 6a)

I agree podster. I think in Cindy's case the water sat in there all winter and it got warm often enough to promote algae growth. Making sure the barrel was empty and/or storing it in the garage/shed/basement would have stopped the growth before it got a good start.

The problem I have with dark barrels is the difficulty in determining how much water is left in it.

Hobart, IN

GK - Thanks for the chlorine advice. First winter with a rain barrel. I did leave the spigot wide open all winter but it's about 5" up from the bottom. And the barrel is painted light gray to blend with the house (aesthetic thing). I had no idea it would get warm enough in there to grow algae over the winter. I'll definitely do the chlorine thing but first I'll try to empty it out totally and give it a rinse or two. Is 2 oz. of chlorine (laundry bleach on my part) enough for a 55-gallon barrel? Also will pass on to my daughter who just installed a 2-barrel system this spring in TN where I know it stays warmer during the winter than here.

Deep East Texas, TX(Zone 8a)

I meant an opaque barrel... sorry. Dark barrels here will make the water temps too hot. In this heat, I don't have problems with the algae growing and have not used bleach. Good to information to keep tho, thanks

Paris, IL(Zone 6a)

As I understand it a painted barrel sufficiently blocks the sunlight from growing algae. A painted barrel equals a blue or black barrel. Algae needs sunlight or time to grow. What was lacking in sunlight was more than compensated with time for yours, Cindy.

I would go with more bleach until you feel positive the existing algae has been killed and removed. Be sure to empty the barrel where it won't hurt any growth you'd like to keep. The two ounces is mostly a maintenance amount assuming the barrel is emptied once a week. You might need to crawl in there with a sponge or brush to make sure the algae is loosened. You might need to do it several times.

Hobart, IN

GK - Since I used pale gray spray paint on a white barrel, I'm sure there's still quite a bit of light coming through. And honestly, I never thought to peak inside to see what was going on. The problem could have even started last year. Anyway, cleaning rain barrel is high on my list next week before spring rains slow down.

Exeter, MO

Algea in rainwater collection barrel or polyethylene tanks. Is virtually impossible to avoid, but can easily be controlled. Painting the tank is an option, but is expensive and not that enduring. A better way is to rap the container with a piece of heavy, light colored vinal floor linoleum. A remnant that can be got at most floor covering stores. Covering the sides and top, will elemate sunlight from getting in. Also a rapping of indoor-outdoor carpeting or other insolating materal under the vinal linoleum will help in keeping the water cooler from the radiant heat from the sunlight on the linoleum.
If using a shipping or storage(HDPE)tank, like I am, remove the tank and cage from the shipping pallet and place directly on the ground. This will also aid in keeping the water cooler. Mine came on a metal pallet. I removed the legs from the plate and cut holes for the lid and down spout and secured the plate to the top of the cage. It protects the top of the tank from any damage, even standing on it.

Hobart, IN

I did start with blue plastic olive barrels and gave them a couple of coats of plastic primer and then 2 coats of house paint. I do add some laundry bleach early in the season but don't want to continually add that. I do have mine up on cement block so that I can get a decent flow out of them. My terrain isn't all level so the little bit of lift helps. Good use of the metal pallet!

San Marcos, TX(Zone 8b)

Algae is eating the crap that came off your roof. If you dont have algae in your barrel, you will have an enormous amount of stink. I promote it unless it is clogging valves.
Green algae is the best.
I really hate the brown stuff.

Deep East Texas, TX(Zone 8a)

I've read mention of using barley or a barley ball in ponds to remove algae.
It is recommended for rain barrels also. I wonder how well it would work.

Hobart, IN

jujube - mine is green algae. I wonder if the moss on my shingles (I live on a shaded lot) contributes to the algae in the rain barrel? I did start with the one shot of bleach when the algae did start clogging the outlet valve. podster - I had read about the barley ball for ponds but didn't know it could also be used in rain barrels. Will have to check out that link. Thanks!

Charlotte, NC(Zone 7b)

I've had a 80 gallon dark green rain barrel for five years and have never had a problem with algae. The water that comes out of it is as clear and clean-looking as what comes from our indoor faucets - although I wouldn't want to drink it. LOL

Mine was purchased from our local County.

Bellerose Terrace, NY

This will be my first time with a Rain Barrel and i think it was a poor choice. I wanted it to feed the AWS system for my 6 Earthboxes so i don't need to refill them all the time. Bought a 50 Gal SpringSaver rain barrel which might have been my first mistake since it has a screen openning in the top. Second is the use of water from the roof for feeding vegatables which isn't safe some say and now algae. Ordered a Fiskars Rain Barrel DiverterPro Kit but cancelled it after reading web sites, i'm confussed now more than ever

Hobart, IN

Sorry to hear about the disappointing results with the rain barrel. I've been pretty happy with mine this season, especially with the some of the drought conditions. DH had read about putting pennies in the barrels to help control algae so he had put some in last fall. I did give them one dose of chlorine bleach back in the spring since my algae problem seemed to have grown over the winter the previous year. No algae problems this year that I can see. I have screen tops on mine as well so other than making sure the roof debris doesn't block the screening, they function just as I hoped they would. We made ours a couple of years ago.

Anne Arundel,, MD(Zone 7b)

Might help if you can add a layer of finer filtration to the water going into the barrel. To keep some of the junk out. There will be dust, animal crap , dead bugs, etc on the roof.
A 'roof washer' is used on really serious systems- it doesn't 'wash the roof' but it diverts some of the initial flow of dirtiest water away from the barrel before starting to fill the barrel.

Hobart, IN

Hmm - interesting. Sort of like pre-screening?
My rain barrels have been dry half the summer - not much rain here.

Traverse City, MI(Zone 5a)

Employ the 'no room at the inn' technique. If you fill your water sources with good bacteria there is no room for algae, fungi and bad bacteria. This is the product I use.

Deep East Texas, TX(Zone 8a)

I think that is an excellent suggestion but couldn't find reference on how much to use per gallon (as in a rain barrel). Any thoughts?

Incidently you might edit your link to have a space at the beginning.

Amazing, I see they are actually nearby me in Texas. Thanks!

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