Since those totes are white it is slightly transparent and will admit light to it's interior, so algae will start to grow on their interior walls. I had a white plastic 55 gallon drum thad did just that. It would be a good idea to also put in a little copper sulfate in to retard the growth and / or cover them with black plastic or spray paint the outside with black paint.
DH & I were just talking about that this morning.
We have seen how algae grows in the white totes, and were planning to put some kind of cover on the totes, to minimize algae growth. Copper sulfate is not a good option, because we are also planning to use this water, for the animals & eventually to raise fish.
We have access to very reasonably priced galvanized sheet metal siding. We can also get a variety of colors. A local metal siding company sells remnants, in 8 foot lengths, for $1.60/foot.
This is the West side of the building, which gets lots of hot sun, during the summer. Black absorbs heat & the last thing we need is to make the water hot. Not good for the garden.
We are planning to screw wood strips to the metal framework & then screw white metal siding to the wood. The white color would reflect the sun, to keep the water cooler, yet not give the algae light, so it couldn't flourish. The wood strips would hold the metal away from the tote, to allow cooling airflow. Win, win!
A friend has a tote, that he raises goldfish in, for aquaponics. He use canvas painter's dropcloth, for a type of curtain, to block sunlight. The problem I saw with that, is that mold is now growing in the fabric.
