Mobile Bay Reef Keepers

Ok I'm upgrading my 20 gallon mixed reef tank from 130 watt power compact system. Which is 65 watt daylight bulb and 65 12,000 k actinic bulbs. Im upgrading to a mh fixture which has 1x 250W 15,000 k HQI metal halide, 2x 65W Actinic Blue CF amps, and 4x Bluemoon LED. What would be the best way to acclimate them. The corals are ora neon green bird nest. Maze brain. Neon green candy cane. Zoas. Green staghorn. Monti capriconis. And blue tip acro.

You'll hear of a few different methods. Some suggest simply shortening the photoperiod in which the halides would be on. This, in actuality, is not an ideal situation because of how photosynthesis works. The process itself is rate limited, not time limited, meaning that shortening the photoperiod will still result in damage, but only lesser amounts. This results in not only a weaker coral from the short photoperiod, but a stressed and damaged one, as well. The better bet is to actually slowly ramp up intensity. In this scenario, the corals are not exceeding the rate in which various chemicals (hazardous ones, like excessive oxygen) can be processed, so there is no damage in both the short and long term. There are lots of ways to do this, including elevating the fixture well above the tank or even using a series of window screens, removing one per week or so to ramp things up in intensity.

Depending how small these pieces are and if they are encrusted into large pieces of rock, you can also move them to the bottom of the tank, then slowly (over a couple weeks) inch them up to the spot that you want.

I also like the window screen method mentioned by Amphiprion.

I like the egg crate screen method and that's the one ima use thanks aura and amp

a 250 watter over a 20. Andrew I believe that is your style isn't it. Don't you guys have any worries of temp issues with this. I'm not sure if there is a canopy or anything in this setup but you might have a hot tank. I don't believe the DE MH put out as much heat as the single ended bulbs but I could be wrong. That seemed to be my experience from a past life. I think the LPS might be the ones with the long term issues. I'm still unable to move my lps up in my tank under 6 T5. 4 are overdriven on an icecap and the other two are on a tek ballast. I run the tek setup from noon to 9:30 and the overdriven stuff from 5 to 9. I had to cut back the overdriven stuff because things started to look bad. I had them up to 5 hours and bumped it down to 4 and the acros actually looked better.

I was gonna have the fixture 12 inches away from the tank and several fans runnin yo help temp control. Also what does "de" mean as fish stated.

De is for double ended halide bulbs. The higher the k rating the less heat. With the fans you shouldnt have much of a heat issue, I have 250hqi over my bio cube no fans and no heat issues. You may want to hide some of the lps in some shaded part of the tank those are the corals i would be worried about.

Yeah, that's similar to what I have, Drew

I actually use a pedestal fan to keep it cool for me, but mine is only about 5" from the surface, so it is very hot and very bright. With the fan, I can keep it at 81 degrees, which is what my heater is set to. To contrast that, it runs at 87 degrees without one, even in the winter. Oddly enough, I have had less issues underneath this halide with various corals than I had with T5s. I bleached things left and right with T5s, no matter how much I attempted to acclimate them. I think it has something to do with the nature of the light in that it hits from all directions, whereas a halide does not (that's conjecture, though). It's not an intensity difference, since this halide is far brighter without a doubt.

Babyreef wrote:De is for double ended halide bulbs. The higher the k rating the less heat. With the fans you shouldnt have much of a heat issue, I have 250hqi over my bio cube no fans and no heat issues. You may want to hide some of the lps in some shaded part of the tank those are the corals i would be worried about.

Actually, they will emit the same kind of heat. The only time you'll get a difference is with different ballasts, which run lamps at variable wattages. They emit the same amount of heat per watt. The same applies to T5s, which also emit the same heat/watt; they just distribute it better. How far away is your halide situated? Anything below 8-10" will definitely create a noticeable amount of heat. It definitely does in mine, even with a Vortech, which creates no real heat in the water and a Tunze silence pump @ 12 watts, but again, it's ~5" from the surface for my grasses. Oh, and the fixture itself will make a difference. For example, an enclosed aluminum fixture will absorb most of the heat and radiate it in all directions. This makes it a lot cooler over the tank. My single-ended fixture has no glass shield, but has a LumenMax style reflector, which is great for reflecting light, but also heat. Makes a big difference in raising temperature as well, especially compared to the AquaMedic DE I was running before, which didn't heat things nearly as much.

Andrew you need to stop by sometime and check out how things have progressed on my tank. The Tort and Rose Milli are really growing but not getting the color I'd like. The rose finally turned a pinkish color from the green it had but isn't getting a nice deep red I thought it would. The tort has nice purple tips with green branches. I have another milli i picked up at progressive a while back. It was browned out and it looks like its getting similar color as the rose. I moved it to the bottom of the tank to see if it would get better color. I've noticed that my sps on the bottom half of the tank have better colors than the stuff on the top half. I haven't bleached anything other than the stuff I got from Zack but that was coming from a VHO only setup. The stuff I got from Andy under his 400 watt bulbs had no problem adjusting. Just some color shift issues.

I changed all 8 of my T-5 bulbs (39 watt) in one swoop and had no losses or bleaching. SPS, LPS and mushrooms fine. Algae started growing faster though.