Barley Clear Planters Small, 7-1/2" dia x 6" high by SUMMIT RESPONSIBLE SOLUTN. $17.84. Size - 1500 GALLON. Barley Straw. Improve your water quality wit this attractive, floating planter. Barley straw planters act as a natural filter, keeping the water in your pond clean and clear. Will not harm fish or plants, treats pond for 6 months. No danger of koi nibbling. Plant houseplants or other non submersible species in planter and release in pond.