Lighting Question for 29gal Tank

[jeffauby]

Hi, this is my first post to RC. I've got a 29 gal mixed reef tank. Its been up for 9 months with much success. I run a AquaC Remora skimmer, have a 10 gal fug, about 50lbs LR, so far so good.

Until last Sunday I had a 130w PC together with a 38w T5 fixture. Overall, it was doing OK, but I was shppoing for an upgrade.

Sunday I bought a used 2x175w Metal Halide fixture. I'm running 14,000k in both. THe tank looks amazing! The shimmer is very cool.

So now I'm playing with my canopy to try to get good light coverage an minimize the heat. Today as I was playing around with this, a question came to me... Do I have too much light? I'm about 10watts per gallon! What are the risks? (Aside from heat) I ask becuase I could modify the unit to only run one MH bulb. If I did that, I could also hook up the t5's and run actinic through them.

Any help, comments are appreciated.

[Bonneville08]

I think its a lot of light, others may disagree.
I'm assuming its mogul base lamps, if they are double ended HQI you might be able to use 70W lamps.
In my opinion a single 175W 14,000K lamp is plenty for a 29 gallon aquarium.
Hope this helps

[LJA]

Welcome,

I myself have had my 29G up for about the same amount of time and had some of the same questions when I started out.

IMO, 2 x 175 MH is too much for a 29G even if you were keeping SPS corals.

I would look at what you want to keep and what you have now and adjust accordingly.

It would be fine to have both if you want, but I would definatly add maybe 2 x 24 T5 Actinic to your canopy if you can and maybe set each bulb on a separate timer so they only overlap in time of being (on) maybe 2-4 hours mid light cycle for you.

I would do something like this:

8am Actinics on
10am 1st MH on
12pm 2nd MH on
4pm 1st MH off
6pm 2nd MH off
8pm Actinics off

Or adjust to whatever 12 hour shift is best for you. This really depends on what you want to keep down the road though. Watts per gallon really dosen't mean much.

Lights should depend on:

1. What you keep
2. Depth of tank (distance from lights to bottom)
3. Your wallet

Personally I prefer T5 HO lights and that what I have on my 29G.

I am certainly no expert, I have just had experiance with this size tank. There are a lot more people that can explain the lighting better than I.

I did see someware on here a detailed list of what depth each wattage of the average MH bulb is good for but this is just what I think it was from my memory:

150W MH max 18"
175W MH max 20"
250W MH max 25"
400W MH 25" +

This is just a guess of what it was I read. Check out GrimReefer in the lighting forum for expert advice.

HTH and good luck.

[jeffauby]

Thanks folks... Good advice. I've removed one of the bulbs and recentered the single bulb. They are Mogul bases, so I had to play with the placement to get even light. Its funny, ever since I've seen the 2x175, everything else looks dim. :-)

I also hooked up the two 24" t5 bulbs. My current bulbs are 1 10k and 1 actinic. I'll buy another actinic.

I'm gonna give this a try. I'm interested to see the temp tomorrow, as today I almost hit 88 degrees with the 2 bulbs!

[jeffauby]

One more question... My ballast is a dual system for the 2 bulbs. Its a basic transformer with capacitor setup x 2. It has one plug going in for both systems and two plugs coming out going to the bulbs... If I only connect one bulb, but still have power going to both systems, I should still get the energy savings and the heat generated in the ballast should derease right? I think this is true... Or do I need to go into the box and disconnect the power going to one of the transformers?

Thanks again!

[returnofsid]

If it's too much light, you'll notice a detrimental effect on your corals. This can easily be solved by raising the lights some.

[jeffauby]

Again, thanks for the help! I'm excited that I joined this site, as the responses have been quick and helpful!

I think I might have answered my own question about the ballasts. First I read a little about them. In theory, they shouldn't use any power if the secondary circuit (load) is open. But in reality they will use some. I ran a short test by plugging in the ballasts (both of them) but not plugging in the lamps. After 2 hours, the system was generating the typical electrical humming noise and it had heated up. Although the heat was less than when the system is actually running, it's definitely using power.

I found where to disconnect the hot wire going to the individual ballasts. Assuming I decide to stay with just one of them running, I'll disconnect the other.

Thanks again!
Jeff

[IslandCrow]

Truthfully, I don't agree that you have too much light. That whole watts per gallon thing has to be taken with a huge grain of salt. You also have to look at intensity. a 175W bulb really isn't all that intense. I have a friend who runs a 400W and two 250s (along with VHO actinics) over his 60g, and his corals look amazing. The only thing I'd really worry about is properly acclimating the corals. I truly doubt a couple 175W metal halide bulbs is going to give you anywhere near the PAR of the sun on even a cloudy day.

I think the real question is whether or not you need that much light. I think that depends on what you're keeping and whether or not you're getting sufficient coverage with the one bulb.