Which continuous pH, TDS and temperature meter is best?

So I'm looking for a continuous pH/TDS/Temp meter and ran into the: HI 991404 and HI 981504. From the looks of it they both do exactly what I want, with the later supporting digital ballasts (something about electrical interference). But with the e-ballast stuff out of the way... which is best? Or is there something even better?

I want to be able to continuously monitor my pH / TDS / Temperature w/o recalibrating the pH part every time I want to take a reading.

Will I be able to mix nutrients while I take continuous readings from either of these? Does either one run a better pH probe than the other?

Hopefully someone has experience with either of these can chime in...

HI 991404


HI 981504

no responses, damn, would of liked to know the answer to that myself

I have the same dilemma! Do you have any new knowledge since then? I'm choosing between the same two units. I do like being able to see all three reading at the same time. But other than that....?