MH lighting ballasts

[I_am_Elmo]

hey do certain ballasts only work for certain K lighting or is it for wattage? eg would a ballast for a 6500K 250w bulb also work for 14000K 250w bulb?

Or more specifically, could I buy lighting from switched on gardener and change the bulbs from the plant ones (I assume around 6000K) to marine ones (14000K)?

[HaNs]

hey do certain ballasts only work for certain K lighting or is it for wattage? eg would a ballast for a 6500K 250w bulb also work for 14000K 250w bulb?

Or more specifically, could I buy lighting from switched on gardener and change the bulbs from the plant ones (I assume around 6000K) to marine ones (14000K)?

All that matters is the wattage of the bulbs

[suphew]

Yes you can do this, you might find it is even cheaper to go to an electrical wholesaler, I recently priced up 400w ballasts at $100 from a electrical wholesaler (no I don't have account etc, this was just walking in off the street).

There are a few things to know, firstly you can get magnetic or electronic ballasts. I haven't priced up electronic but expect they cost more. However they use less power, give off less heat, and are far lighter, I have also read that your bulbs will last longer and keep their colour longer. Next with some bulbs (DE 250w I think) there is a 'German' and 'Chinese' version that use slightly different voltages (and therefore current) if you have the wrong bulb in the wrong ballast it wont last nearly as long. Lastly like most things ballasts are not all created equal, plus some brands of bulbs work better in some ballasts, cheap ballasts can shorten bulb life, etc, etc. But the problem is in NZ there is almost not selection so unless you want to import ballasts IMO buy the cheapest you can find, it's probably the same as the more expensive one anyway.

Some light reading if your keen... http://www.reeflightinginfo.arvixe.com/index.htm

[Warren]

hey do certain ballasts only work for certain K lighting or is it for wattage? eg would a ballast for a 6500K 250w bulb also work for 14000K 250w bulb?

Or more specifically, could I buy lighting from switched on gardener and change the bulbs from the plant ones (I assume around 6000K) to marine ones (14000K)?

The same ballast can be used if the bulb operating voltage is the same and the wattage is the same. I have come across bulbs that operate at different voltages before for the same wattage. If this happens you will get two things happening - the bulb life will be lengthened or shortened depending on whether the voltage is higher or lower (will also effect the power in the bulb) and the colour will be wrong due to the arc operating at the wrong temperature. This is more typical of boutique lighting systems so you have to use their expensive bulbs...

You need to get the full technical spec for the bulbs you plan to use and make sure the operating voltage is the same. If not then you'll need to change the ballast to suit as well. The impedance of the ballast is set to create the correct voltage on the bulb and is critical for the correct life and colour.

[I_am_Elmo]

All very helpful although very confusing, I think I'll get my sparky dad to sort it out for me