Dymax pH Meter

[Carz]

I'm considering a pH meter and saw the Dymax pH Meter and like the black colour, blue led and slim looks very much cos it goes very well with my black Fluval Edge with modded blue moonlight LED. I'll be keeping shellies in pH9+/-.

However, I got a few qns before buying:

1. I read from Wiki "Calibration should be performed with at least two standard buffer solutions that span the range of pH values to be measured" However, lfs and even Dymax showroom comment only need pH7. So do we need 2 points calibration for accuracy? If using only pH7 is not accurate, won't it then defeats the purpose of using a pH meter. Who is correct?
2. I see Pinpoint pH Meter has pH10 calibration i.e. pH4 & pH10 uses the same "slope". Dymax's only has pH7 and pH4 buffer solution and not pH10. Does that means it does not allow the same? If so, will it affects accuracy between pH7 and pH10? If it allows the same, does that means I should use other brand buffer solution for pH7 and pH10?
3. Double confirm Dymax's probe can be full submerged in water?
4. Is Dymax's an OPR meter as well but need a different probe?
5. Anyone knows of a similar good looking pH meter that I can consider?

Thanks!