SpectraPure® LiterMeter® 4 Programmable Precision Dosing Controller - LM4-01

I've used a couple of different models of dosing pumps for pH buffering, and found the liter meter 3 the easiest to use, routinely service, etc. The 4 is hard to use, with the online adjustment system pretty strange in comparison to other digitally-adjusted dosing pumps. We swapped since we invested heavily into the 3, and found we needed to upgrade our entire stock to the 4 and it was expensive and not worth the trouble