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!

Dumbarton, VA

I wanted to collect enough rainwater to use with a small orchid collection, deck and porch plants, and when making fertilizer & compost teas. I use a grey 32 gal. Brute trashcan to collect overflow from a valley section during heavy storms on 2 sides of my porch. I use the Brute can, dish tubs and a couple 5 gallon buckets to collect additional and then pour in to Brute can but we have had so much rain this year, keeping the 32 gallon can full has not been an issue. As to issues with algae - none really but then I just went simple and used an $88 Loweís deck umbrella - I have shade and an area to work and the can does too. Each morning (my barrel in on the south/west side) I go out and raise it thus it keeps the sun off the can and helps the water stay cool. It still gets sun first as the sun comes around to the deck and then late afternoon when the sun is coming through from the other side but no issues. In the beginning, prior to the umbrella, I used about 2 oz of chlorine bleach (make sure you get plain - not cleaning bleach or scented with pinesol, etc). But then I read it is good for a biofilm to develop and that will keep things in balance but I donít know about that - have to do more reading. That said, I never used anymore and the water is clear as tap water. No smell, etc. There might be a little green on the sides I believe but not enough to really see. As this is not really a system, I just dip the water with an old white porcelain coated pan - you know the old fashion kind with red handle and rim that had begun to rust. It works great and I use it for water, potting soil - anything I need to dip including compost tea or fertilizer solutions around plants. I was raised by my grandparents (born 1905 & 1913) - simple works just great. For filtering, I just tied an old sheet over the top - if I get time - one day might cut it the right shape and run a piece of elastic around it - it would make several. In the meantime, I just twist the fabric up and rubberband or use those giant office clamps. It stays on all night or day if raining - when the sun comes out it dries enough to pull off and shake out the huge amount of debris (especially when crepe myrtles are blooming) from gutters, let it dry and wait until the next rain. Sometimes during lots of rain I just lay it over the can and other buckets - once wet it stays in place. If I donít do that, I just leave it on the big can and pour the water from the smaller containers through the sheet to filter them if needed. For mosquitoes - I use BT mosquito dunks and crumble them over each container - the amount is based on the surface size not the volume of water but the directions will tell you. I havenít been able to find the bits this year locally and 1 dunk has lasted with my pond, birdbaths, and all these rainwater collections - each rain I have to add more because it gets run off and this year it has been raining every couple of days. You know, I think I may have moved to Florida and someone forgot to tell me! Sad...this year not much needs watering. Whether I need water or not, each rain I leave the top off to refresh. In terms of emptying the barrel, I have a pump I got from pond shop I use to empty pond. You can also get a piece of tubing and work it up and down quickly to prime and the water will flow out - it is a little finicky and the tubing needs to be long enough to go from the bottom of the barrel and out to the ground but it works well and much quicker than those silly taps that come on most barrels. I had livestock and when the well pump went bad we would have to fill 55 gal drums at home and carry to the farm. Some areas didnít have electricity and we emptied the drums into the water tanks from the back of the truck using this up/down movement to start it flowing. Get a better valve and it will flow much better - check local plumbing warehouse. You can also get a non electric hand pump type aquarium type device to empty. I have used one of these and once the water was flowing - set it into a plastic gutter pipe extension (the kind that are like an accordion and you pull it out to the length you want). These also can be bent a little to fit through my deck railing openings into the concrete gutter spillway or into the gravel drain area I have under my spigot I had placed on the far side of the deck. I had it placed out there so I wouldnít have to have the hose across the deck. In 20+ yrs the copper pipe hasnít frozen but it is the south side and I cut the water off inside and leave the tap open all winter and the holes were cut to allow a bit of slope but not much. So there are several ways to go without getting fancy or electrical - someone mechanical else might have other ideas. Also, barley balls do work but they need to be the right size and at some point have to be replaced - for rain barrels I donít know due to the volume and the fresh water being changed out so frequent - at least small ones. They work based on microbes so you donít want to use chlorine nor any other sanitizer and again, constant fresh water may be an issue. The best estimate I have seen is a 1Ē rain on a 100 sq ft roof will generate 600+ gallons of water - needles to say - that will fill a 55 gal barrel a few times over even if just one collection point but a friend has one at each downspout a

This message was edited Jun 27, 2018 4:08 AM

Decatur, GA

I've had rain barrels for years and they get a thick layer of algae. I ignore it for the most part, but a couple of times I have disassembly everything and power cleaned most of the stuff out.
I figure it's just natural and nothing to worry about. Occasionally the spigot slows up and I use a thin wire to dislodge debris and keep the water moving.

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