Best way to stop algae in water troughs

[Spottyappy]

I have metal auto fill water troughs. This year, I am struggling with stopping thick, green, gloopy algae from growing in one in particular.
2 have covers on, so when not in use, they are not exposed to the sunlight, so algae is not a huge issue, but it is an issue none the less!
The other one doesn’t have a cover, as the horses are using it. The base and sides are covered in green when it’s empty, and no amount of scrubbing removes it, which obviously means the algae regrows quicker.
I Don’t want to get goldfish. I have read bleach may help, but I’m really not keen to put bleach into drinking water.
Any ideas appreciated, in particular on how to remove the very stubborn green algae stuff which remains even when emptying,washing and scrubbing the tank!
TIA.

 

[millikins]

Green algae won't do your horses any harm, but if you find it unsightly or it's clogging the mechanism you could try barley straw which inhibits the growth of algae. You can buy neat packages of it online or from aquarists' suppliers.

 

[asmp]

If it floats on top I have a sieve in the field which I use to scoop out any bits ((plus insects, leaves, the odd bird that cant get out! etc.)

 

[Red-1]

I don't have the luxury of automatic waterers, but have to scrub my field water XL trug out every 3 days or the algae sticks. The other 2 days I just top up.

 

[Shay]

You can get a barley straw block from any aquarist or garden center - but the horses may pull it out and eat it!

 

[Spottyappy]

Thanks, will try the barley straw, I think.

 

[Cbig]

This sounds silly but it works!
Put stones in the bottom of your tank...normal stones off the field, a good layer.
We did this and our tank has been clear as a bell ever since.
We have replaced the stones last year when the water went cloudy. The stones that came out were covered in a calcium type hard growth. I have no idea how it works and was very sceptical when advised to do it, but it works for us.

 

[Spottyappy]

This sounds silly but it works!
Put stones in the bottom of your tank...normal stones off the field, a good layer.
We did this and our tank has been clear as a bell ever since.
We have replaced the stones last year when the water went cloudy. The stones that came out were covered in a calcium type hard growth. I have no idea how it works and was very sceptical when advised to do it, but it works for us.

Thank you, that is an unusual resolution. Can I just ask if you are in a hard water area? We are.

 

[Toby_Zaphod]

very so often I empty the troughs & in between I keep a cheap sieve near the trough & I scoop the offending weed off the top.