WaterSafes are only good for one use, since you can't dry them out and mold will form.
One of the simplest water collection units is an above-ground swimming pool. A pool 48" deep x 12' across holds just under 3,000 gallons of water.
And keep in mind that there is a difference between algae and moss.
Algae is the stuff that grows in the water and makes it a cloudy green, and sometimes it forms in strings; this can be deadly toxic.
Moss grows on the sides of the water storage tank in clumps. Moss is a cleanser of water. It was discovered in WWI that soldiers whose wounds were packed with spaghnum moss had a higher survival rate than the wounds packed with cotton bandaging material. That has been translated into a new way of
cleansing water .
That's a big plus for those of us who live in the PNW. It grows on anything that holds still long enough.
Sue