6 gal, 70 watt hqi, and SPS?

[iBryant]

Guys,

I made a 6.5 gallon acrylic tank/sump, have a 70-watt JBJ vipper, and would really like to keep SPS. The water parameters, sand bed, live rocks, etc have been consistently good now for four months, and I figure I can now add some acroporas. However, I am not sure if this lighting setup is best, or if two 70-watt vippers or a 150-watt lamp would be better for growth and color. Can you tell me what works here?

Thank you!
Bryant

[sir_dudeguy]

70w MH over just a 6.5g tank is plenty for anything imo. vipers arent the best (just cheap is all) but they still put out enough light imo.

[Eskie]

I agree with dudeguy. 70W will be plenty over a 6g. Anything else in the tank other than LR and sand?

Also, how's the evaporation from the 6g under the MH?

[iBryant]

This sound good, and I will move to buy some acros and buttons too! I do have a blue neon goby, peppermint shrimp, hermit crab, and a couple snails.

The vipers’ reflector does not form any kind of parabola over the back half of the bulb. It seems from what I’ve skimmed here about reflectors this is a very important omission. The bulb did actually shatter on the second day of running. I do not know what goes into evaluating whether the ballast is good or bad, but I would like to eventually get into it.

Only about three cups of water evaporates a day, and I am running the lamp about 3.5” above the water. I would like to try running the lamp lower, about 2.5” from the water, and add a small pc fan (40mm x 40mm) or two. This way I can remove the viper’s pivoting arms all together, because it looks a little funky to me. I never read about anyone running metal halides so low. Do you know of a reason for this other than heat? Is it a problem with ultraviolet light that gets by the lamp and bulb shielding?

Thanks sir_dudeguy and Eskie :)

[Eskie]

Three cups, a pint and a half, is a lot to evaporate daily. A fan will accelerate that evaporation. I'd be concerned about the swings in salinity in a tank that small over the course of a day, but while an ATO would be great, but given the typical size of float switches, I don't know how to set one up in that size tank. I'm sure someone else has a solution.

Running the light that close to the water will certainly increase heat transfer, and there will likely be splash and salt accumulation on the lens/UV glass on the fixture. You'll probably also see salt creep inside the fixture. That could be a problem. As far as excess UV exposure, if the correct UV glass lens was used, I don't think that by itself would be an issue, but the goby will probably want sunglasses. Is there any way you can keep the fixture elevated 3 or 4" more? Your corals won't gain anything from setting the lamp that low, and it can really open you up to more trouble than it's worth.

[herostar]

It will work, but don't expect awesome results.

70w is still 70w regardless of tank size...

[iBryant]

Herostar,

I am really interested in getting great color and growth too. Have you heard of or seen 70w's used and not work so well? Or have you see 150w lamps work with a tank around my size? I read about one 10g tank that used a 150w but it wasn't clear about how the SPS were growing.

I was initially considering using two 70w Vipers to kind of control the light on the left and right side of the tank like they do with the large tanks, or just going with one 150w. If needed I will get a chiller. What do think?

Eskie,

Right now, I am using Aquamedic's doser to replace evaporated water, a little bit ever hour. This seems to work well.

[iBryant]

Herostar,

I looked up your 10g pictures and it looks like you have an acro and a green monti plate that are doing great. What lights are you running?

Thanks, Bryant

[sir_dudeguy]

Three cups, a pint and a half, is a lot to evaporate daily.

i havent been reading this thread other than this line above. I just wanted to say that i dissagree. That is pretty normal. During the summer i get over a gallon a day on just a 40g tank w/20g sump. While yours is only a 6g tank yes, i still dont believe that it is that much. But having an auto topoff unit will help keep stuff good if you want sps. If you get that much evap in your tank, i wouldnt try sps till you can get a topoff to keep it even.

[iBryant]

I just found a thread where Dr.FuManchu and smketyr both say they would like a 150w on their 10g.

The idea of using two 70w sounds like it would be quite flexible, like offsetting the start and stop times for the dusk to dawn effect, or running a 20k in one for more blue. I think this would also light both sides of each coral, which seems would be healthier for the corals somehow. Kind of like how the real sun moves overhead sunning multiple angles. Also, one side could be run even less during the summer months.

I've been topping off with a doser. So far this has been good.

http://reefcentral.com/forums/showthread.php?s=&threadid=1017303

[ELCHUPACABRA]

I have a 2x 70W MH on my tank with 32w of PC super actinic, and it is great! I have a lot more light spread than 1 150wMH. I am upgrading my 15g from that to a 400w 20k MH as soon as my corals sell on n-r classifieds. Check out the light on my thread, I am going to be selling it very shortly. http://www.nano-reef.com/forums/index.php?showtopic=96328&hl=el+chupacabra