Snails multiplying

• pH:
• Temp:
• KH:
• GH:
• NH4:
• NO2:
• NO3:
• PO4:
• Iron:
• Dosing: 10 mL Flourish, 20 mL Excel, 7.5 ppm NO3, 1 ppm PO4
• NO3:PO4 Cumulative Dosing Ratio: 22.5:2.8 = 8

Notes:
Manually killing a lot of snails lately, don't know how to eradicate snails without killing the shrimp as well...

It seems that I probably have ramshorn snails: Snail ID

There doesn't seem to be any good way of removing the snails except by perhaps trapping them, i.e. baiting with lettuce or zucchini and removing attached snails several hours later.