Pond Boss Forums INTRO Questions & Observations Killing Algae in Drip Irrigation Water

I draw water from our creek and then transport it to tanks that utilize a drip irrigation system for my various tree plantings at the farm.

The running creek had a tiny bit of algae in it, but my tanks were always dry before an algal bloom formed in the tanks.

However, the creek has quit flowing and I now can only draw water from the deep pools. These pools have recently exhibited awesome algal blooms. There is no longer any place in the water column for me to draw clear water.

The water is a little green when I fill my hauling tanks, but the algae are continuing to bloom in the irrigation tanks - and becoming thick enough to plug my drip emitters.

Questions:

Will covering the irrigation tanks with tarps to cut off the sunlight be sufficient to kill the algae?

I may have to flush the empty tanks with a little bleach and dump it out before re-attaching my irrigation tubing. This should kill the algae that is in the 1" of water that remains in the bottoms of the tanks. However, is the dried algae on the sides of the tanks "dead", or will it once again begin actively growing when I fill the tank with water?

I actually pump water to an elevated tank by the creek, and then dump water from that tank into my truck hauling tanks. I was considering putting a little bleach in the elevated storage tank to kill the algae prior to loading the water. However, concentrated bleach is toxic to small trees. I don't know if there is a dilution level that would make it safe to trees. However, the diluted bleach water would probably still be harmful to the beneficial organisms in the root zone.

Is there a chemical I could add to the elevated holding tank that would eliminate the algae, but NOT be harmful to the trees or beneficial soil organisms? (I am imagining a chemical that breaks down after x hours into non-toxic components.)

Thanks for the help,
FishinRod

Not sure this will help, but I add apple cider vinegar to our chicken's water, and it greatly reduces the algae.

I wonder if purifying the water with bleach would be a possibility for you. Prepper types do this for drinking water and it takes very little beach per gallon. My thought is if it can be made drinkable for humans...the trees would be fine, but the algae might have a hard time with it. Not to mention, city types have been watering their lawns with chlorinated water forever.

When I had aquariums, it was common knowledge to let city chlorinated water sit for a day or two, open top, and the chlorine would leave the water and could be put in the tank with the fish.

Something to look into at any rate.

Thanks for the advice, everyone!

I have been watering with chlorinated "city water". My usual practice is to load my truck tanks in the evening, and then leave early in the morning to water the trees. That gives the water a little time to outgas the chlorine. However, my water needs have gone up greatly due to my additional tree plantings plus the drought at our farm. I must utilize my supplemental water supply at the farm to save time and gas money, but the system definitely needs some tweaking.

Preppers use bleach in their water supplies and the water remains potable to humans. However, bleach is an effective herbicide.

The most efficient lake algaecides are frequently copper based. Yet copper sulfate is the active ingredient in the products that kill the tree roots in sewer lines. Fortunately, some of these algaecides are marked as safe for irrigation water.

"The dose makes the poison."

It appears that my best option will probably be to mix my chemicals at very low rates and see if they can be effective below the recommended treatment concentrations. If not, then I will slowly walk up my concentration.

I also believe getting the tarps on my distribution tanks should be a priority - since there are no negative side effects to denying light to the algae.

FishinRod, I been wanting to do the same thing, been hauling water from the pond with a tank and just watering fruit trees and blueberries with a garden hose, but was wondering if a person couldn't do some kind of drip tubing, wasn't sure what to us for that, I have plenty of scrap pieces of the drip tubing that I install for pressure sewer dispersal systems but that needs to have pressure behind it to get much out of the orifices, plus with the algae buildup inside the tank in the sun I assume they would clog up pretty fast. tried to find a soaker hose today but couldn't find any of those either.

Could you fill the tanks with a garden hose at the farmhouse?

gehajake,

My drip irrigation system has been working almost flawlessly with clean source water.

I use the 1/2" poly drip irrigation tubing to run my lines. (.700 OD, 500' for $34 last year) Put it out in the sun the day before you plan on doing the installation job - you want it soft and pliable.

I can punch holes with the little tool and install two 4 GPH flag emitters at each tree in under 60 seconds.

The system components are actually designed to run at 25 psi. Therefore, you must elevate your water supply tanks. I just built little stands about 5' tall from old 4x4s from a scrapped fence and placed them on the highest ground around each stand of trees. That is only 2.15 psi hydrostatic at the bottom of the tank - but it still works!

I have timed my tank flows and I de-rate the published emitter flow rates 70-90%. However, that doesn't matter, I just put more time on the battery operated flow valve.

The operating pressure is so low that you can't have a hump in your line where you go over a little rise of land. It will air lock your system. (You can open a connector there to purge the line and get it flowing, but I just avoid that situation in the design now.)

There are little ells and tee barb connectors that you can easily push in by hand. At my operating pressures they have never come apart or even leaked.

It definitely beats truck-watering 200 trees during a drought!

The old farmhouse collapsed before we even bought the place. We don't have any electricity service out there right now.

However, I agree that modern AC electricity is a miracle cure for most problems like this. I did test the old well by the house a few years ago. The static water level is just above the bottom of the shallow well. The water I test pumped was very dirty. In hindsight, I now think that just might have been topsoil that worked into the well through some holes in the casing. It might be capable of producing clean water if I ran the pump for an extended period.

I may have to explore your idea sometime in the future.

Do you know the opening size in the drip emitters? (in thousandths of an inch or microns)

I couldn't find those specs on the manufacturer's website.

They do say the filter requirements are a minimum of 150 mesh.

I have had good luck with these inexpensive filter screens at 155 mesh. They are easy to disassemble and flush, and then clean the filter if needed.

Dig Filter Screens

I also use the DIG brand flag drippers. They can be twisted apart to be cleaned. I also like running two per tree. If one plugs, it is easy to catch during a visual inspection when the other one is merrily dripping away. (Plus the tree still gets a drink from one dripper when I don't walk my lines often enough.)

Thanks for the link FishingRod! I gotta set up something like that for my fruit trees and blueberry patch, put a lot of money and effort getting them started and it got pretty hot and dry this summer, everything is still looking good but for the most part except for a few young Blueberry plants.
I did water them a couple of times with a garden hose, I just use a 250 gal tank on a skidloader, fill it out of the back of the pond dam I have a pipe and valve out of the bottom of the pond. I set the tank up on stack of pallets to get a little flow and water by hand. I see where you use a battery valve but I think I can just fill the tank about two thirds full and let it run empty every time, might cut back on the algae growth in the tank.

Pentair AES sells filter bags and filter bag housings. You could maybe get a few bags, one housing and use them inside the holding tanks to filter the water going to the drippers.


https://www.pentair.com/en-us/produ...ation-cartridges/liquid_filter_bags.html

gehajake,

Yes, I agree that taking the time to set up an irrigation system from your tank will save you a huge amount of time in the future watering blueberries and trees. I think you will achieve "payout" for your time in about a week!

That filter screen I linked is usually in stock at our local Home Depots.

I have installed battery timer valves on my far-flung tanks. For the tanks close to my normal work routes, I just open the tank valve and hit the timer on my phone.

For people that do not have AC electricity at their pond or water source, I have had very good luck with the cheap 12V submersible sump pumps from Amazon. They are capable of producing a good bit of vertical lift. I can do multiple tank fills over a 2-week period with a deep cycle battery. A solar trickle charger would probably allow me to use the battery for 9 months without ever taking it in for juice on the AC charger.

My advice would be to get a tarp over your tank ASAP. If using an IBC tote, you could probably even wire scrap plywood to the top and sides of the metal frame. If it is too ugly and in sight of the house, let the kids/grandkids paint a picture on the plywood before you attach it. Blueberries that they "helped" grow will taste even sweeter than regular blueberries!

Mine is one of those round top sprayer tanks, and its not unsightly and 25 miles from my house, nobody will see it anyways, its pretty much hid from the rd, but letting them paint on it might be kinda neat, as for the filter, I think I actually have a couple of those housings laying around here, we use them in the pressure drip irrigation sewer systems that we install, with a lot finer filter in it of course, too fine for gravity water. I might have to see if I can get a screen for one of them. I have tons of leftover drip tubing too with the emitters already on it but those emitters are exactly on 2' spacings and will put out about .5 gph at 25 to 30 psi, so they wont put out very much at all, if any at 1/2 a psi.

With your drip irrigation septic system experience, you could set up your drip watering system very easily.

I would buy new tubing - it is cheap. I also use the 4 GPH drippers to get decent rates (though much less than 4 GPH).

The most surprising thing to me was how "idiot proof" the system was. I was worried I would have an improper design and have to tear it out and start over. Instead, you just make a ball park estimate on your drippers per blueberry bush. If the bush at the terminus of your line is not getting enough water, just add another dripper. If one bush dies, then just pull out the drippers there and stick in some goof plugs. They don't leak at all at my operating pressures.

After you set up the system, CLEAN water is your only concern. Before my algae problem, I did have one system clog the filter when I started it in the spring. The IBC tote on that system had originally contained a paper finishing chemical. I cleaned the tank very well before installing it. There was just a very thin film adhered to the plastic. Unfortunately, over the annual summer expansion-winter contraction cycle, the film peeled off of the tank in small pieces. The filter screen caught it, but I had to pull that tank and take it home for a "re-cleaning".

Have fun raising a big crop of blueberries!

Thanks, hopefully between me and the birds and varmints, one of us will have some blueberries to eat one day, I actually got a couple off of one variety that must bear a little earlier, smaller plants even when full grown.

Them tanks can be a mess to clean, I had to clean this one out after having set for a couple yrs with a little water in it to haul water to pressure test a water main we installed last spring, took a steam washer with the gun on it curved to a ninety degree angle,, that makes them pretty hard to hang on to but does work great for a lot of tight spaces when it comes to cleaning equipment and such.

I have trouble on the IBC totes on the initial cleaning!

Tire shop guy gave me one that held the chemical they use to make foam-filled tractor tires. So not worth it. Never got it clean.

I like the ones with oil products in them. I leave them in the hot sun, then drain to my oil pan. Rinse the bottom 4" twice with a lot of Dawn dish soap. Then fill it overnight with some Dawn in the water. Those are always clean when I drain them the next day.

I have been lucky, we have a guy here local, my neighbor, that gets those totes from where he works at that had food grade stuff in them, those are the easiest to clean, I mostly use those for storing and handling waste oil, I have a waste oil furnace for my shop so I go thru a lot, even more then I create with my equipment. those dont have to be as clean, I usually just drain everything out of them and filler up. what I meant about cleaning that other one up, it had to be all but sterilized so as not to contaminate the water main, I had to do a water quality test for the water district on the new line afterwards.

Hello.

You ask: Will covering the irrigation tanks to cut off the sunlight, be sufficient to kill Algae.

Yes...... My little pond for Yellow-perch fry.

Half is in the sun, the other half is in the shade.

In the sun you can see lots of Algae, in the shade no Algae all summer






A+

Thanks azteca.

I love your little pond projects!

We had a cool day yesterday with rain, so I worked at the farm and wrapped two of my tanks with tarps. It appears that the little 6x8s I bought will give me 100% coverage.

However, looking at the pictures of your project, I wonder if I couldn't actually try to reduce the algae in my source water? The largest remaining pool in my creek is in a very protected area. I suspect I could suspend a large tarp over most of the pool.

On the other hand, that pool is now the main fish "refuge" in our stretch of the creek. The secchi disk reading is probably down to 2-3". The tiny end of the food chain has to be getting a good start in the pool right now with the algal bloom. I want all of those organisms to go forth and multiply once the creek starts running again!

gehajake,

Glad you can get the "food grade" totes. There must be a lot of demand for those in my area, because the prices are ridiculous!

Drip water for trees and drinking water for humans are two different things. Obviously, you have to start with food grade.

I do have one bit of "tank" advice for anyone that may read this thread in the distant future. I have had excellent luck with a product called Rhino Tuff Tanks.

They are stackable, made of much thicker plastic than IBC totes (no metal cage needed), and have threaded 2" inlets and threaded steel 1" outlets. Even better - they come in a range of sizes. I have 80 gallon tanks, 120s, and a 160.

The 80 gallon tanks are my favorite for the systems I have described above. They are easily handled, and I can put them on 5' stands by myself. When I observed the algae problem in one, I just loaded it in the pickup, strapped it down, and cleaned it at home.