Got my MH up

[jmt]

70w MH + 9w Acintic = Amazing.

 

The pics do NO justice b/c the camera adjusted for light balance.

 

Nipple... it IS angled up.:

[jmt]

Stepped back:

[jmt]

Little closer:

[jmt]

the $1 condy:

[jmt]

The light fixture is mounted sideways for now (I goofed on the mounts). I'll make new ones and get it mounted correctly.

 

-Justin

[jmt]

Here it is correctly mounted:

[jmt]

The expensive lexan from Home Depot WILL NOT work... 800F my ass. I melted it~

 

Frontal:

[jmt]

So much for High Heat Super Strong Lexan (After 10mins) -- No, I'm not naked.

 

:

[rehren]

what fixture is that?

[jmt]

it's hard to tell, but i did some reengineering. The PC ballast is now remote and the MH nipple is angled up at about a 60d instead of about 15d. The bulb sits higher off of the lexan (1 1/2" as opposed to 1/4" before) so it shouldn't melt. I also cleared some holes to mount a fan.

 

Repositioned:

[jmt]

Fan hole:

[rehren]

what fixture is that?

[jmt]

9" PSL 2x13w (www.petsupplyliquidator.com) -- I had it from an old 5ga tank.

[jmt]

lexan combust heat:

[ravenlot]

Is your Lexan sheet the XL10 stuff that you can get from Home Depot? That's what I put in mine a couple of days ago. It seems to be working really well for me. The sheet doesn't even appear to be that hot. Did you face the correct side towards the light? It only has the protection coating on one side.

 

Birdman204 (One of nano's of the month) uses this stuff. I PMed him to find out if he still likes after all this time. He told me he still uses the same sheet.

 

BTW, my Lexan sheet is about 4 inches away from the bulb.

[jmt]

Mine is a lot closer (approx: 1 1/2"). Heat resistant side? Mine melted and warped on both tries. Yes it is the lexan xl10. Is there a heat resistant coated side?

 

-Justin

[ravenlot]

I don't know if it's a heat resistant coating or just a UV coating or both but only one side has the coating. When I bought the sheet, the side with the instructions and info was the uncoated side. The side with the green protective film was the coated side.

 

At 1 1/2" distance and such a small enclosure, I could see why heat would build up. I assume you would be using a very small fan with this hood (around 40mm computer fan). While better than nothing, I kinda doubt that would be enough to remove enough heat from such a small space.

 

As far as the 800 degree temperature claims of Lexan, I still feel this is accurate. My guess is that these MH bulbs are at least as hot as halogen bulbs and those can reach over 1200 degrees from my understanding. That's not to say that I don't think the Lexan stuff is good enough. I think quite the opposite, actually. But it does have to have some clearance and the 4" clearance works for me.

 

Last week, I had an aluminum hood somewhat like yours but longer. Just as yours, the bulb seemed to mount very close to where the glass/plexiglass would go, about 1 1/2". It just seemed too close for me. I ended leaving off the lens and just covering the tank so that there would be some ventilation. Even with the open space, the area above the tank seemed really hot as did the glass cover. But that's not all. The setup was dangerous because it exposed UV rays to anyone looking at the tank. My eyes were affected and I got a very slight sunburn on my forhead The next day, I built a wooden hood that sealed off almost all extraneous light (some light comes out the back). There was more space between the bulb and tank and the Lexan sheet blocked the UV rays. I added a 70mm fan for extra safety but it was cool enough without it. Now, the top of the hood doesn't even get warm. The Lexan sheet only gets lukewarm, not hot to the touch like the glass did. I'm planning to add actnic supplement; hopefully, the setup will remain cool.

[jmt]

redone again

 

plastic quick connects removed:

[jmt]

down1:

[jmt]

down2:

[onthefly]

Ahhh, I remember the first MH days! Sunglasses on, staring into the tank!

 

JMT - get some 1/8" glass from HD. That's works just fine!

[jmt]

I don't think the UV glass from HD can withstand the heat or I would get it. I have to find some tempered glass at a glasshop somewhere.

[onthefly]

My bulb is 2" or so above my glass. It gets hot...but, hasn't cracked or broke yet (going on 4 months). Also, regular glass if fine. You don't need "UV glass", that to keep your couch and pictures from yellowing.

[rehren]

um - you do to need UV glass...

 

look around and you'll find plenty of instances where people ran double ended bulbs w/o UV glass only to kill off and bleach things in their tank.

[onthefly]

rehen - Do you think that the thin layer of glass around SE MH bulbs is some "special" glass? What about the glass that covers halogen household fixtures? No, it's just glass!

 

When I switched over to MH, I totally had the problem of UV damage, for different reasons. I've tried several types of materials. After PM'ing several of the mods over at RC (one guy is a retired phyisist), and several replies where people had great results with regular 1/8" HD glass (example: one guy had 4 250W DE'rs over a 75ga) Regular old glass is a VERY good filter for shortwave UV....the harmful stuff. It doesn't stop UV C, which is why you're couch or pictures will yellow if left for "months" in it. DE bulbs are incased in quartz (actually high quartz - HQ). Quartz will emitted UV all the way down to 214nm, and I'm sure high quartz will go even lower. So what you want is something that absorbs/scatters those wavelengths. After that you're in the visible range, and we want that! That is why, in science, we have to use quartz, not glass, to do UV spectrophotometry. All glass does is absorb and scatter UV light. I guess my final example is a screw up I had a few weeks ago. I forgot to replace my glass top and put the MH hood on the tank. Within 5 minutes, all the SPS, zoo's, ric's shrooms, bascially everything was closed. I then saw my glass sitting on the dinning room table Replaced it and everything opened up over the next couple of days.......there are several examples at RC of this exact same scenario, all of them with regular old HD glass.