Adding a 150W halide to an existing fixture

[sinkingbeach]

I currently have the older model Aqua Medic Spacelight dual 250 Watt HQI, with 2 24watt pcs in the center. My idea came from their new Ocean Light http://www.premiumaquatics.com/Merc...duct_Code=AM-75055&Category_Code=Oceanlight-h

So my questions is can I remove the pcs and add an additional halide, I was thinking an Ice Cap ballast placed externally. I also wondered if having a halide in the middle will become a "spotlight" with a different colored bulb(was thinking 50k 150Watt Double End - Iwaski) from the other 2 if anyone is familiar with that chime in. thanks

 

[DaveK]

I don't see why you can't do this. I have a couple of Aqua Medic fixtures, and I've upgraded all the original ballasts to electronic ballasts. The HQI ballasts did need to be mounted externally.

I highly recommend you also upgrade the existing ballasts to electronic ballasts. The Aqua Medic fixtures of this vintage were originally built for a European market, where 220v power is common. To make them work in the USA they added a step up transformer to take the 110v we use and convert it to 220v.

This is an extremely inefficient way to do things, because a transformer is only about 65% efficient, and you have two of them for each MH bulb. So the math works out to this -

250w bulb / 65% ballast / 65% step up transformer = 592w input power needed.

if you replace that with a electronic ballast, which is about 90% - 95% efficient the math works out this way -

250w bulb / 90% ballast = 278w input power needed.

That's per bulb, so you save a bundle in electricity, and heat created by the old equipment. You'll pay for the electronic ballasts in under a year.

In addition, your fixture will drop a lot of weight, making it a lot easier to deal with.

 

[sinkingbeach]

Instead of adding a 150w I went with another 250w giving me a total of 750w. The only issue I seem to have is using a single 14k Phoenix bulb in the center with 2 Geisman 14k bulbs on each end is giving me the spotlight effect I was concerned with. The Phoenix is much bluer than the Geisman's. I think I need to switch them all to one brand of bulb so it looks uniform, comments or suggestions appreciated.

 

[DaveK]

Yes, I could see that happening. I'd pick the light I liked best, and change the other bulbs to that.

You might also be able to rearrange the whole thing and get 4 250w mh's in there and alternate the bulbs in them, but that's a lot more power consumed, and heat produced.