cool thanks for recommendation, that model is out of stock, might pick up this one by apera which looks like less accurate -.1 vs -.01(apera 60) but think should be good enough
SX610 Waterproof pH Pen Tester, ±0.1 pH Accuracy, 0-14.0 pH Range, Suitable for Test Tube Testing, Replaceable Probe https://www.amazon.com/dp/B01ESYG6B0/ref=cm_sw_r_cp_api_i_i0JIFb2EDB46Q