Help with lighting questions for a Hex tank - advice needed

[EricMack]

OK, the good news is I have a free new 42G Hex tank. The bad news is the light, and what can I do about it. The current light is an 18" fixture, and since its a Hex, I don't think I can do much about that. It throws off a measley 15W

I want to have plants in the tank, so I need more light. Alas, the only solution I have found would be to retro-fit the current fixture with a 36W single fixture from A H Supply. This will more than double the output I have now, but will it be enough to keep plants happy?

Any thoughts or suggestions would be greatly appreciated.

Eric

 

[oscarbreeder]

It may be ok for some low light plants.
But you should have 3 watts per gallon to grow most live plants.

 

[grimlock3000]

Well in a hex tank you do not have much horizontal area for plants anyway, so I think you can do pretty good with a 36 watt light. Think of it this way, you are getting 2 watts per inch of light length. I have a friend with a 30L and his plants grow like weeds with a 65 watt bulb, that is 1.8 watts per inch. Here is a pic before a pruning:

The AH Supply lights really help you get the most from the bulbs too.

 

[Medusa Head]

I have a 42 gallon heavily planted hex.

Since the tank is 24" deep, it needs a more powerful light to penetrate down to the bottom.

I am currently using a Custom Sea Life (I know, they are out of business...) 250W Metal Halide / Power Compact Prism Pendant combo. The unit measures 17.5" across and is 13.5" deep. I don't have it hanging, I have it sitting directly on top of the hex glass. It fits perfectly on top of the tank. I have a HOB Aquaclear 300 filter on the back. To open the tank, I just lift the light up and prop the back end of it on the Aquaclear. If I need to take the top off, the fixture is light enough that I can turn it vertical and set it down on the Aquaclear with the back resting against the wall.

Here's a small pic of it on the site where I ordered it, of course it isn't available there now:

http://www.aquarium-supply.biz/ordering/lighting_CS_Metal_Prism.html

It came with a magnetic 250W ballast and I am using it. The lamps I am using are: for the metal halide, a 250w 6500k Iwasaki, and for the Power Compacts, two 13" 32W Ultra Actinics. I have actually tried different combinations and temperatures of MH and PC bulbs, and I found that this combination gives me the best results. I do get some green algae buildup on the glass hex tank top every few days, but it's not too hard for me to wipe off. I know there are many people who say Actinics do nothing in FW tanks, but to me they give the tank a cooler look and I think they enhance the spectrum... I think they help simulate blue sky and they are supposed to trigger chlorophyll production.

The PC and the MH sections power on seperately. It has a fan and it's on the PC circuit. I have a timer hooked up to turn the PC's on at 8:00 am and off at 9:00 pm, and I have a timer on the MH turn on at 9:00 am and off at 8:00 pm.

You can order the same type of fixture by Blueline:

http://www.championlighting.com/e/e...nk=/Products/productinfo.html&item=main:pp250

I don't recommend the electronic ballast "upgrade," I believe you get more light output from the magnetic ballast.

I also use an automated pressurized CO2 system @ 3 bubbles per second, yielding me about 15 ppm CO2 level. My tank temperature is 76°F. My lighting does not raise the tank temperature.

My plants:

5 Cryptocoryne Wendtii
2 Echinodorus Osiris
2 Anubias Barteri v. Nana
1 Aponogeton Madagascariensis
1 Cryptocoryne retrospiralis
1 Bunch Vallisneria Spiralis
1 Bunch Vallisneria Americana
1 Bunch Egeria Densa
1 Bunch Bacopa Monnieri
1 Bunch Heteranthera Zosterfolia
1 Bunch Cabomba Pulcherrima
1 Bunch Lysimachia Nummularia

There's plenty of room for them. The nice thing about the deep tank is the stem plants can grow nice and tall.

Here's a pic I just snapped of the fixture sitting on top of the tank:

 

[chasgood]

Will a 20" fixture fit?
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=11420&Ne=40000&R=2775&N=2004+113345

 

[Medusa Head]

Remember the "watts per gallon" doesn't apply as much in this tank because it's twice as deep as standard tanks (24" as opposed to 12").

A 20" PC-only fixture will fit fine because it isn't as deep as the halide pendant-hood. I used to use one but upgraded to metal halide as the light just wasn't penetrating very good down to the tank bottom. I found it to be somewhat adequate but not great.

I wouldn't use a fixture that sits on a stand, it really needs to set right against the hex top's glass to penetrate down to the tank's bottom. I used and would recommend a PC 20" dual 40w model.

The link you posted to Foster & Smith shows that all of their 20" fixtures are on backorder. They are also 36W. Not saying it's sure to happen, but in my past experience, once the "due date" arrives, Foster & Smith is likely to just bump up the due date and post another "due date."

Check this one out, it's $105 and even has a moonlight: http://www.championlighting.com/e/e...k=/Products/productinfo.html&item=main:20sat2

There's three plugs so you can hook each lamp up on a timer and control them individually.

The biggest problem I find with this fixture is lack of bulbs for it. It needs 18" 40W pc bulbs, preferably both in the 6500K range, and I can't find anyone who makes one. The closest I can find is on the same site (Champion Lighting) and is a 6700K/10000K combo - http://www.championlighting.com/e/e...ink=/Products/productinfo.html&item=main:40da. This really should be fine, but I would be happier with all 6700K.

I wouldn't recommend combining white and actinic with this fixture on a FW planted tank, especially on our 42 hex's.

Foster & Smith says their fixtures come with "6500K bulbs," but I can't find any replacements anywhere on their site in either 36 watt or 40 watt strengths that are 6500K. They do list 40 watt 6500k / 10000k bulbs, but they don't include the lengths, so these may not be the correct 18" size needed for a 20" fixture.

 

[EricMack]

Wow, thank you all. Medusa, thanks for pointing out the 20" at Champion. I need to look into this. I will have to call them to find out the dimensions, since the description on the site is kinda Sketchy. I poked around on Champions site, they do seem to have the 18" bulbs you mentioned. I hope the fixture is not too wide, as the current fixture with (and glass) are 4" wide. Do you have one of these?

 

[EricMack]

Does the Moonlight have any application in a FW tank? Does it bother the fish?

 

[Medusa Head]

The 20" model will most surely fit. As I mentioned, I used to use one before I switched to metal halide. It fit the tank top with no hangover. When I say "wide" I mean across when standing in front of the tank. I call the other dimension "depth."

The one I used to use was again a CustomSeaLife model, 20" wide and a depth of 7". The halide I now use is 17.5" across and is 13.5" deep, and again it fits the tank top with no hangover.

The moonlight looks great in the 42 hex at night with the lights off. I just think of it as a nightlite for the fish in a FW system.

 

[EricMack]

Hmm, this is sounding more fun all the time! The hood I have has a glass panel that is only 4" depth. You are right, that 20" light has a depth of 7.5." So, I take it I will need to cut off some of the plastic hood so that the light is unobstructed. Good thing I have a Dremel. I will go home and check this out b4 I order. I think it should work. Wonder what the Lunar Light looks like? Cant find a pic of it on their site.

Thanks so much for pointing this out. I now have a ray of hope!

 

[Medusa Head]

I'm not sure how your hex tank top is different than mine, but it should not require any modifying to use either the 20" PC fixture or the 17.5" MH prism pendant.

I just took this pic of my 42 hex with metal halide lighting (again, a 250w 6500k Iwasaki MH bulb + two 13" 32W Ultra Actinic PC's):