Murphy cup, yes, but you still need a hydrometer. The Murphy cup only tells you what the hydrometer should read at the temperature of the sample, you still need a hydrometer. So, get at least a hydrometer, then add a Murphy cup as soon as it fits your budget. In fact, I always have 2 or 3 hydrometers, in case 1 gets broken.
Dave Klish, I recently bought a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.