Glass under MH retrofit?

[percula]

I recently purchased a coralife MH retrofit kit (2x250w) and in more than one place it included the disclaimer "NOT FOR USE OVER OPEN TANKS". This is my first MH fixture but I have never seen anyone or even a picture of a glass top under one of these. This is not HQI so I assume it's not a matter of uv. Am I missing something?

 

Thanks, Matt

[Almon]

I use glass in between my Metal Halides and the water, but I think I am the exception to the rule. I do it to reflect the heat. The disclaimer is probably warning of the potential for exploding if the bulb gets splashed with water.

[dshnarw]

Yep - it's a liability issue for the company. Just like the "Warning - contents may be hot" notices on coffee cups, they're avoiding potential lawsuits.

[fab]

Contact the manufacturer and get your information from them. Otherwise you cannot be sure you know what their issues really are.

 

fab

[FishWife]

Generally speaking, why don't folks use glass. We have glass tops for our used bowfront, and are trying to make pondnetting tops to replace them because... everyone doesn't use glass...?

 

What's wrong with glass, especially since we're using Dan's Standard 8 and so oxygenation's not an issue.

 

Afterthought: won't the glass protect from "environmental" stuff in rooms getting on the water AND keep fish in?

[flowerseller]

I think it's because anything Coralife"less" is suspect.

[Rascal]

Generally speaking, why don't folks use glass.

 

My reasons:

 

1) Heat.

2) Maintenance.

3) Light (as in - less of it, when you don't keep up with #2)

4) Gas exchange.

[Almon]

I think most people believe that 1) glass will interfere with the light, reducing the amount of light that reaches the corals, and 2) it reduces the gas exchange at the surface.

 

I personally believe that while glass may reflect some light and refract some light, plenty of light still reaches my corals. And I never believed that the gas exchange was reduced, at least, not in my setup.

 

Again, I am the exception the rule. There are many positive aspects to having glass, reduction of heat into the system is one. It's also a guard to keep fish in, and cats, among other things like environmental stuff, out.

[wreck]

I think if you aren't having a problem with elevated temperatures during daylight hours and you keep your glass clean that you should stick with the glass top that you already have. I think pondnetting might pose a fire hazard depending on your light setup and also a fish hazard if it happens to droop into the tank. I had to save a Koi once that got tangled in the netting. Most people use white eggcrate(aka open square light diffuser) that can be cut to fit. I have a two piece glass top under my metal halide just to be on the safe side in case of splashes and to help keep the salt off the bulb.

Wreck

 

Generally speaking, why don't folks use glass. We have glass tops for our used bowfront, and are trying to make pondnetting tops to replace them because... everyone doesn't use glass...?

 

What's wrong with glass, especially since we're using Dan's Standard 8 and so oxygenation's not an issue.

 

Afterthought: won't the glass protect from "environmental" stuff in rooms getting on the water AND keep fish in?

[FishWife]

I think if you aren't having a problem with elevated temperatures during daylight hours and you keep your glass clean that you should stick with the glass top that you already have. Wreck

 

Please define "clean." Like, do we need to rinse them daily? That's a pain. We don't have halides: we have a six-bulb T-5 fixture suspended about 5" off the tank. Would eggcrate melt? How about looks? Everything about our tank is black... can we spraypaint it?

[davelin315]

Any fixture that is close to the water should and exposed to a lot of moisture should have glass between it and the water. This is to protect the bulb but is mostly to protect from salt creep and moisture getting into the wiring and causing arcing. ANY fixture can suffer from these problems. I am speaking from experience on this, but I also think that part of it is from less than stellar equipment when dealing with coralife fixtures. I had a coralife fixture catch on fire in my home in the spring and I attribute it to salt creep in the wiring. The wire itself caught fire and the GFI failed to catch the moisture in the wiring.

[wreck]

I rinse and wipe down my top like once every week or two. The eggcrate was designed to be used under lights so I don't think it will melt, lots of people use it. For looks, glass looks the best..I'm sure you can paint eggcrate but no personal experience painting the stuff.

Wreck

 

Please define "clean." Like, do we need to rinse them daily? That's a pain. We don't have halides: we have a six-bulb T-5 fixture suspended about 5" off the tank. Would eggcrate melt? How about looks? Everything about our tank is black... can we spraypaint it?