[GregD]

Ltspd or others,

I was following a couple of threads on some of the other BBS to build a DIY HQI shield or reflector.

??Did you ever have any luck finding a shield or light pendant from HD or other places that you could retrofit and use with an HQI setup?

I currently have an HQI setup with a PFO pendant and glass shield however the pendant is getting much hotter than I like so I am trying to see if there are any alternatives....

Thanks in advance!
Greg D

[Ltspd]

Greg, wish I could be of more help but I am setting up a full canopy with the HQI lights. I think BillZie is doing a "pendant" style light but he is having the same issue of heat.

I did fab up a quick single enclosure for the HQI's but that was when I was under the assumption that the UV issue was more than it turned out to be. This was to reduce the amount of glass needed for the enclosure. Since I just got my tempared glass at a cost of 40.00 its was cheaper in the long run to fully enclose my whole hood. IMO you should do this with ALL mh bulbs.

From what I have been told by others the HQI pendants dont give much of a light spread compared to full hoods/canopies.

[GregD]

Cool....thanks for the information.

This kind of puts me back in the same dilemma I started with.

I built my own custom hood for the tank....I was thinking it would be easier in the short term to mount a pendant hidden within the hood. It seems that the better option is to really build the reflector and light into my hood and glass off the entire bottom of the hood?

3 more questions if you don't mind....

1) What retro-reflector did you use for your HQI

2) What kind of cooling do you have in your hood? (this is really my issue that is driving me to make changes)

3) What does the glass shield do to your PAR and UV strength of other MH's and any VHO's if you have any?

Sorry for all the questions...I really appreciate the help and agree with many of the conclusions of prior threads on the subject.

Thanks,
Greg

[scubadude]

Hope you dont mind if I jump in here I just wanted to lay out some links here in case you might have missed any, they are all related to your inquiry.

diy reflector

HQI & U/V ray Shielding

http://www.reefcentral.com/vbulletin...threadid=32376

http://www.reefcentral.com/vbulletin...threadid=38440

http://www.reefcentral.com/vbulletin...threadid=37990

I think the one issue I wanted to help (or atleast throw in my advice) you with is ques #2

The idea is to VENT as much as possible, these bulbs get very hot. Everyone knows that hot air rises so if there is a quick escape then you will save yourself alot of trouble. I have small pieces of block between my reflector and canopy and 2 fans on the top of the canopy sucking air out of the canopy....there are a few small holes in the reflector which will allow some air through the reflector area, but not much most of the air circulation is between the canopy and the reflector (not inside the reflector) These bulbs supposedly will cause problems and decrease life expectancy if you blow air directly on them. HTH

[Ltspd]

Greg
1) What retro-reflector did you use for your HQI

I am using some spectral aluminum I got from a MO supplier. I dont have the address and cant remeber the name right now. It cost me 50.00 to cover my 60 x 22 hood bent in the shape of \__/\__/ with the mh's in the center and the actinic's on the outside.



2) What kind of cooling do you have in your hood? (this is really my issue that is driving me to make changes)

I will have lots of vent holes. (4) opening will be where my fans are now, which is in the ends. I will also bore several other holes in the back and will more than likely install a Radio Shack fan in the top. This will pull air from the back of the reflector, without pulling directly on the bulbs. It should be enough to cause a fairly good draw flow pulling hot air out.


3) What does the glass shield do to your PAR and UV strength of other MH's and any VHO's if you have any?

Regular glass allows around 90% light transmittion thru the glass itself. This is greater than standard acrylic which allows about 83% if I remember correctly. The UV reduction is I think about 35%, but I will have to check my charts at the house to verify. This is about the same as the outer casing on most mh bulbs. There are some that are covered with borasilicate glass (a dip) that reduce more. The kicker is that most of the good UV reduction casue's further reduction in pass thru light/PAR/etc. This is true with acrylic, which reduces 75% approx UV rays but further reduces the pass thru. The problem with acrylic, and why I did NOT use it, is becasue acrylic can only handle approx 300 deg F. These bulbs and others get hotter. I just wired up (3)400w Iwasaki's for a friend, he has 1/2 acrylic and after just a few hours the acrylic began to "bow" It will also cause the stuff to spider and frost from what I have been told. The tempared glass will not, and should last much longer and is overall cheaper than the acrylic. No, it does NOT reduce as much UV rays, but it does provide enough to keep from short term exposure while working on your tanks. According to Eric Borneman, the corals handle UV well, they are subject to it in the wild (Sun).


I hope to work on this over the weekend, depending on how poor the weather is and what my wife has for me to do I will be taking pictures of the whole process as I complete it.

[GregD]

Thanks Scubadude and Ltspd....your replies helped me tremendously!

Greg D

[Ltspd]

Glad we could help. Let us know how it goes and what you decide to do.

[scubadude]

Yes i agree w/ Paul....definately let us know what you decide ....I am very interested

[GregD]

Thanks guys...I will keep you posted !

I think my first step is going to be to add better ventilation to my existing DIY hood. I have a single ICEcap fan running inside the hood now. (pretty lame flow, just haven't messed with my original installation due to laziness factor)

I definitely need to build better ventilation into the top panel. Even before posting I realized I was trapping a fair amount of heat in the top of the hood because it had no where to go. So...

Step 1 - Add vents to top of hood...I think I may try and find some slim vents used for the eaves of houses at HD...this should enable me to paint them to match the hood (black gloss)

---------------------------------------
I have also been putting off upgrading my fans to move air. It seems that to go the way of hood fans, pc fans or radio shack fans all wind up with the same result...anywhere between 3-8 fans in people's hoods. I think I may see if I can find a single larger fan that fits and is quiet (easier said than done I am sure)

Unless maybe there is logic behind the multiple fans...for example I could see the logic of 2 fans (one to push and one to pull air from the hood)

Step 2 - Search for medium fan to use in hood
Any suggestions...??

Thanks in advance!
Greg D

[Ltspd]

I use the hosfelt fans, the 115cfm ones. I cant say I am thrilled with them. They do a great job of pulling air and keeping the tank cool. The problem is they are very loud IMO. I only have 2 of them running not the 4 I originally thought I would need. To me it sounds as if I am in a airport

http://hosfelt.com/Fans/115vac.htm

I would use the radio shack 3" or 4" fans if I had it to do over. They are much quieter, maybe because they dont pull as much air (CFM)

I dont know much about IC fans other than they are varible speed based on temp. This is a nice feature, meaning they dont run wide open unless they have to. Of corse they are expensive.