nminusyplusm
Crowing
That's what I was afraid of... if they can tip the whole tank, blocks wouldn't stand a chance.One of my mares likes to play in the 150 gal. tank! She will sometimes tip it over if it's down to 30% full or less. She has broken a heater too! I can see her messing with the blocks in the tank. If the OP has less playful horses, it might work well.
Mary