View Full Version : 6 or 8 bulb, dimmable or non dimmable. HELP!

11-27-2016, 04:31 PM
Hi all,

I'm looking for a nudge in the general direction of an ATI fixture and I can't convince myself of which one to go for.

I plan on buying a 55 gallon tank (36Lx20Hx18W) and want to get an ATi fixture to go above it.

I know that most would normally say 'the more bulbs the merrier' but is it really needed? I'm thinking, although it wouldn't be a tonne of difference, if I don't need 8 bulbs then why bother paying for the extra electricity and bulb costs if it isn't needed.

So I guess my question is, for an sps tank of that size would you go 6 or 8 bulb?

Now onto part 2......

Dimmable or non dimmable?

I like the dimmable for the single reason that it uses one plug for both circuits and fans. The non-dimmable uses a plug for each of the two light circuits and then a third plug for the fans.

However, with the price difference between the two I could buy an eb4 and the non-dimmable and the plug issue is a moot point plus I would now have an extra outlet spare. I don't think I would even use the dimmable feature anyway.

Let me know what you would do and help me stop internal dialogue in my head as to what to do.

Muchos gracias,

11-27-2016, 06:03 PM
Go 8 bulb and non-dimmable. You can never go wrong with the extra two bulbs for color configuration and you can just raise the fixture higher above the water instead of dimming.

11-27-2016, 07:05 PM
Agree, 8 bulb, non-dimming.
Their 8 bulb fixture is almost 18" wide. The dimming can be a cool feature, but not needed, and maybe not worth the $$. If an 8 bulb is too bright, raising the fixture, or just using an old bulb or two can mellow it out.

11-27-2016, 07:26 PM
The dimmable only wastes bulb life

11-27-2016, 10:51 PM
The dimmable only wastes bulb life


11-27-2016, 10:54 PM
8 bulb for sure though Duncan , more bulb combos and just better coverage. If it wasn't going to be an sps dominant tank then maybe a 6 bulb would do. Or another option is to go with the 6 bulb and add a Reefbright strip. I just ordered a Reefbright and it will be here on Tuesday. I'll let you know how it works when it gets here.

11-27-2016, 11:14 PM

You have to know what your doing. To break the bulbs in there a trick I don't know what it is try reef2reef otherwise your bulbs last only 6 months or so

11-27-2016, 11:29 PM
You have to know what your doing. To break the bulbs in there a trick I don't know what it is try reef2reef otherwise your bulbs last only 6 months or so

Just need to run bulbs at 100% for about 50 hours. That will break them in and then it's fine to dim them.

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11-28-2016, 04:11 PM
Fwiw, I love he dimming feature on my ATI. I have 6 bulbs on 21" wide tank. Plenty of light. I get 250 PAR on the sand (19" water, 21" tank height, fixture is 4" off the water).

11-28-2016, 05:12 PM
8 bulb Dunc I am running 6-48" t5s it's lots of light but sps will appreciate more. I've added 2 ai sols for more blue at night plus a 250 halide in the middle for me 6 was not enough, did i mention the tank is only 12" deep par must be way up there.

12-06-2016, 06:50 AM
I love the dimming feature.

Perfect for acclimation and it allows me to have a longer viewing time.

12-07-2016, 03:24 AM
Hey Dunc
With an 18" wide tank and 20" high (close to my tank with 8 bulbs), I say you need 8 bulbs for SPS.
6 bulbs won't cover the spread enough, unless you are planning on only LPS.

If you buy an 8 bulb unit, I can help you re-wire it to control each ballast ...
Instead of 2 bulbs 'on' and the other 6 bulbs 'on', we can rewire your fixture as I did mine.
I run 4 ballasts on 4 cords and 4 timers.

As far as dimmable goes, I'm not convinced/swayed about the life of the ballasts and bulbs, so I'm staying away from that option for now.
I've only ever thought about it as I would like to have my lights dim from the last pair in the evening to 'off' when the fish need to go to sleep. But I'm not going to waste my money on a ballast at this time.
As far as your fish and coral are concerned, I don't think they really care.
Think about all the years of Reefers running MH fixtures that are either 'on' or 'off', yet they've had super successful growth.

Save your money and avoid the 'dimmable' feature

Buy an 8 bulb unit and we will re-wire it for you so you can control the ballasts, thus eleviating your concern about running all 8, and you can be cool like me :wink:

12-07-2016, 05:18 AM
I just bought an eight bulb unit today, I figure I can always remove two bulbs if I want and it's not much more to purchase the eight bulb unit. Or if you like the blue look you can run a couple actinics instead of higher par bulbs. I haven't looked into it but apparently there are also new LED "bulbs" that will plug into T5 fixtures so you can go that way also.