The MA from the Home Depot here is full strength 31% - $5.50 per gallon in 2 packs. Check the garden section.My local pool company sells muriatic acid for $6.50 per gallon that is 31% HCl. You can buy at that price by the gallon or in boxes of 4 - one gallon jugs. Much cheaper than Home Depot's 10%. Virginia (state).