Too much light?

[davefan13]

I will be purchasing a new 55 gallon tank soon, and I will also be getting two 175 watt metal halides. They are run on "tar" (don't know what these are) ballasts.
my questions....

what in the h**l are tar ballasts?

are two 175 watt metal halides too much for a tank this size? i have never dealt with metal halides, or reefs for that matter, so if someone could clear this up for me, it would be great.

 

[rsw686]

I've heard 2-3 watts per gallon for soft corals and 3-5 for hard corals. With that light on the 55 your in the 6 range. That should be fine, but I'd wait for another response to confirm it.

 

[davefan13]

yes, ive heard this to. That is why i wanted to check. i don't want to give my corals a sunburn

 

[Icefire]

2x175 is good.

 

[davefan13]

sweet. hopefully i will get some good growth from corals. I was originally planning on just having t5s. I am glad that i got these, though becuase now i will be able to keep . . . . a CLAM!

 

[BeanAnimal]

A "tar" ballast is a "magnetic" ballast. A magnetic ballasts main component is a large inductor, sometimes with capacitors and an ignitor circuit in some cases. They were called "TAR" ballasts because they were commonly "Potted" with black epoxy or a tar like compound. In other words the raw ballast components were put in a metal can and then the "tar" was poured in to encapsulate everything (or at least the inductor).

If you do not know what an inductor is, think transformer.

To be more precise... the "tar" (now usually expoxy) was used to hold the inductor together and keep it from vibrating.

Many times when these ballasts failed (esp the older ones). The "tar" would get so hot that it oozed from the shell and made a sticky mess. The potting compound has changed a bit over the years but they are still called "tar" ballasts.

 

[davefan13]

ok, so do i need to be worried about all of these getting too hot and making a sticky mess?

 

[BeanAnimal]

No, you will be fine. Most are potted in epoxy now and are FAR from resembling the old fluourescent and arc ballasts that coined the term.