I have a question please excuse my lack of knowledge but what should i look for in MH Fixtures that will allow me to run mercury vapor or other suitable bulbs? I understand the concept of pairing the ballast and the bulb but get into a gray area when we talk about running both.

Thanks so much for all your help!

According to US lamp standards:
- Probe-start MH fixture can be fitted with MV lamp oof the same power category (here i mean, then 360W MH is the same "power category" as 400W MV, even if the nominal wattage is different).
- Pulse start MH ballasts are not compatible with other technologies (you might find combination, that electrically match, but need adoption and generally lack the safety certification)

According to European standards:
MH are nearly exclusively "pulse start", so not compatible with MV at all. Generally they are made based on European HPS ballast specifications (be aware, these are different from US HPS standards), so electrically are compatible with HPS. However for MH is recommended ballast thermal protection (or other means of fire protection from ballast overheating on the rectifying lamp) and higher voltage ignitor.
However there is one exception: 400W power rating is made in two varioants. One around the HPS specification (as above) and the second is build around MV ballast specification with the necessity to add an ignitor if one want to convert MV to such MH.
So (to answer your question) in Europe MV can be run only in fixtures designed for MV.

Thanks! Has probe Start been mostly phased out? I seem to have a hard time finding any fixtures.

You won't find any new probe start MH fixtures here, its all pulse start now. But you can still get probe start MH ballasts new and you will probably find those and maybe some probe start MH fixtures on ebay.

What designates a ballast as probe or pulse start in the description ?

Thanks

A probe-start lamp uses a starting electrode, placed near one main electrodes. That way the OCV is much lower, because only ~ 220V is needed to start an arc between the starter electrode and the main electrode next to it. From then, the arc easily jumps to the opposite main electrode (which takes a fraction a second).

The pulse start lamp lacks that starting electrode. You then need an ignitor (similar to those found in HPS fixtures) to generate a high-voltage pulse that will directly start the discharge between the electrodes.

Hope this helps

A probe-start lamp uses a starting electrode, placed near one main electrodes. That way the OCV is much lower, because only ~ 220V is needed to start an arc between the starter electrode and the main electrode next to it. From then, the arc easily jumps to the opposite main electrode (which takes a fraction a second).

The pulse start lamp lacks that starting electrode. You then need an ignitor (similar to those found in HPS fixtures) to generate a high-voltage pulse that will directly start the discharge between the electrodes.

Hope this helps

Yes it does thanks! Does the CW in the ballast designation mean probe start?