Is algae a problem?

I figured I could find an answer to this somewhere on here but after looking for a few minutes, I could not.

I have 2 275 gallon IBC tanks for catching and storing rainwater from our roof and using in the garden. The water passes through a window screen filter to trap big stuff and then heads straight into the tanks. The tanks are on the north side of buildings, but still grow a reddish algae and other funk. My logic calls that plant food and I haven’t worried about it until now. Now I’ve read of so many people trying to prevent algae growth and I can’t figure out why. Obviously, if the goal was drinking water then I would filter more and try to treat/prevent algae. But I’m just running this water through a hose and watering vegetables, herbs and trees with it. I figured algae could clog a drip irrigation system, but we dont have one yet so I’m not worried about that.

So basically, my question is: is algae/filthy rainwater bad for plants in general? Or is it just added nutrition?

I think you're totally fine here. Algae tends to only be really troubling when it's a big bloom, so as long as you don't have something like a thick floating crust of it you (let alone your plants) should be fine.

If the algae population is balanced there is no issue for you use case,
but if they take over they can start to die off again and therefore deprive the water of oxygen.
Not ideal for plant, but i woudn't worry too munch.

I don't think there's too much to worry about, given what you're using it for. I would keep an eye out for blue green algae, as it can produce some really nasty toxins and could be dangerous to your health, maybe cause issues for the plants too, though I'm not sure on that latter point. It's actually a bacteria, cyanobacteria to be specific, but most people call it an algae and it would probably look like that to most. It's quite distinct looking, so I think you'd know it if you saw it in your tanks.

Matt Todd wrote:I think you're totally fine here. Algae tends to only be really troubling when it's a big bloom, so as long as you don't have something like a thick floating crust of it you (let alone your plants) should be fine.

I never noticed a crust floating on the surface inside the tanks, but honestly didn’t look in there very often during the growing season. There is however a reddish colored crusty layer all around the tank now that it is empty.

Heather Sharpe wrote:I don't think there's too much to worry about, given what you're using it for. I would keep an eye out for blue green algae, as it can produce some really nasty toxins and could be dangerous to your health, maybe cause issues for the plants too, though I'm not sure on that latter point. It's actually a bacteria, cyanobacteria to be specific, but most people call it an algae and it would probably look like that to most. It's quite distinct looking, so I think you'd know it if you saw it in your tanks.

I haven’t seen much blue or green algae, its all been a rust color. The tanks actually have a crusty layer of it around the inside now that they are empty.