Metal Halides and Aquarium Top

[jared69]

Hey all. I've been reading about aquarium covers recently and I've read a whole lot of everything trying to figure this out. I recently got metal halide lighting for my tank (2x250w pheonix 14k). I currently have a glass top on the tank but I was reading about glass tops blocking out light (I'm not so worried about heat buildup).
I saw a few other option for tops such as mesh tops, egg crate and no top at all. The lights sit ~5" from where the top would be so I am concerned the lights would melt any netting or maybe even the egg crate. I'd also like to make sure that I am not blocking out a whole lot of light. I do plan on having wrasses so I worry I will have some jumpers. I am currently thinking about putting egg crate 6 inches in from the rim on all sides to prevent jumpers but leave the centre open to let light pass through.
Let me know what you think!
Jared

[asonitez]

Originally Posted by jared69

Hey all. I've been reading about aquarium covers recently and I've read a whole lot of everything trying to figure this out. I recently got metal halide lighting for my tank (2x250w pheonix 14k). I currently have a glass top on the tank but I was reading about glass tops blocking out light (I'm not so worried about heat buildup).
I saw a few other option for tops such as mesh tops, egg crate and no top at all. The lights sit ~5" from where the top would be so I am concerned the lights would melt any netting or maybe even the egg crate. I'd also like to make sure that I am not blocking out a whole lot of light. I do plan on having wrasses so I worry I will have some jumpers. I am currently thinking about putting egg crate 6 inches in from the rim on all sides to prevent jumpers but leave the centre open to let light pass through.
Let me know what you think!
Jared

If you are not much of a DIY'er... Go to BulkReefSupply and purchase one of their pre-fabbed mesh tops. It comes with everything you need to build a mesh top. The mesh and the spline are extremely forgiving if you messup and need to re-do it.

Alternatively.... you can go to home depot in the screen door section for the rails and corners. Then hit up the gardening section for some black bird netting.

1. 5" from the water surface for the Halides? I'm surprised you are not getting heat issues. My Halides are almost 14" from my water surface to achieve this effect. I would remove the glass tops and do the mesh screen. I would also raise the halides if you have a standard 24-26" tall tank to even out the light dispertion. Don't use eggcrate because the squares are too big and allows fish to jump through.

Mesh dosen't block any light. Its like saying would a cobweb throw a shadow in your tank. I've been using mesh tops for years on all of my tanks. I find ANYFISH is a jumper. I've seen Wrasses, Hippotangs, Yellow Tangs, Clowns, Firefish, Neon Gobys, Triggers all jump lol. I've saved most.

[Jutt123]

I am currently thinking about putting egg

[asonitez]

IMHO the eggcrate would block light not to mention look ugly. The mesh is invisible for the most part

[jared69]

I can do can do some DIY stuff. Just concerned about the heat making the mesh sag. Plus I'm in Canada so shipping from brs is 50 bucks. And to be honest I'm not sure if the meshes I can see on the Home Depot website would be aquarium safe / heat resistant / would not sag. If mesh is the best way to go Then I'm wondering which mesh is the best with halides and if anyone's knows what kind of mesh are good (ex I found fiberglass mesh). Worst case Ontario I could hang my light from the roof and do a mesh top. Still hoping I don't have to order it from brs though.

[jared69]

Originally Posted by asonitez

1. 5" from the water surface for the Halides? I'm surprised you are not getting heat issues. My Halides are almost 14" from my water surface to achieve this effect. I would remove the glass tops and do the mesh screen. I would also raise the halides if you have a standard 24-26" tall tank to even out the light dispertion. Don't use eggcrate because the squares are too big and allows fish to jump out

Forgot to mention, the halides would sit about 6" from the surface of the water (they are not up yet, just waiting for an apex to control my heaters) do you think that would still be too close? I might just have to see how it goes.

[FranktheTankTx]

That's awful close to the water surface = lots of heat X fer to water.

[SaltTinker]

Not to mention the salt spray or splash. All that heat from a MH and one bad slash and the bulb will crack.

I've got my 3 250w MH 12" from the water and I have had this happen twice in 14 years to XM bulbs and 1 other brand.

[tkeracer619]

My halides are not much further than you intend to place yours. My mesh nets need reworking every 6 or so months. Not a really big deal, it takes maybe 10 minutes per cover (i have 3).

Crate won't work well and will block tons of light. It is actually called light diffuser and is intended to make light less intense.

BRS is not the only source of the mesh but it is definitely the way to go if you want to keep your wrasses. Just putting egg crate around the sides won't do anything, they will still get out. I've seen them jump straight through egg crate. It also gives you great practice when you need to actually replace a screen window in your home.

You will need a glass pane on your fixture to prevent bulb breakage from splashes.

[Incaico]

My MH are about 10 inches and I use egg crate. No problem. It is a little ugly but I have a canopy so you don't see it.

[tkeracer619]

When you run a halide you want to take full advantage of TIR (total internal reflection http://en.wikipedia.org/wiki/Total_internal_reflection). By putting egg crate (light diffuser) between a halide and the tank you demolish the angles needed to create TIR. You end up with high light under the halide and low light in the surrounding areas.

I custom built my reflectors with this in mind. I've tried using purchased reflectors and they just don't cut it. Either need to keep them too high or too low. It is hard to get it just right but the rewards are well worth it.

If anyone is curious try this (and be very careful doing it). Hold the halide and reflector while on in a dark room above the tank. Lower the reflector until the room goes dark and the tank lights up. The effect is pronounced and you will see what I am talking about.