Metal halides or not

[wunroch]

I just changed one of my 210 gallon reef tanks into a discus tank. Tank is 72 inch long, 24 inch front to back, and 28 inches high. Put a bunch of easy plants in tank swords, annubias, java fern. The tank currently has 3 175 watt 10K metal halides. I just bought 5 3 inch juveniles from Marks Discus and put them in tank. Do you think I should leave he metal halides or change back to flourescent or power compacts. I know some articles say metal halides make discus nervous, other articles say it is fine. i use RO water PH 6.6, 86 degrees temperature, 6 sponge filters and overflow to pump in sump that I have cut back the flow. I want the plants to do ok but my main concern are the health of the discus. Love to hear some comments.

[plark]

Discus have sensitive eyes, That's a lot of light for them. I'd say T5 max or less with a 6500k bulbs for the plants

[Lytehouse]

Discus have sensitive eyes, That's a lot of light for them. I'd say T5 max or less with a 6500k bulbs for the plants

I think this is a great topic... sensitivity of Discus eyes---

With all that is written on Discus, does anyone have citings in books/articles about this? I'd really like to read up.

Thanks

[Don Trinko]

I do not have metal halides but My discus have shown no preference as to the amount of lighting. Several tanks have only room lights. When I turn the tank lights on for cleaning they do not hide or seem to care. Don T.

[rich815]

I too think MH may be too much and too bright for discus.

I had 4x54W of T5 over my 72 gal (with CO2 and EI fert dosing) before I had discus and it proved too much with me battling algae of all sorts as a result. Plus the darn plants grew WAY TOO fast too. I cut back to 3x54W and things were better in terms of algae and such. Then I got discus for the tank and found them to be very shy when the lights were on and barely coming out mostly hiding under the driftwood and larger plants. I dropped down to 2x54W and to my surprise all my plants still grew fine and most importantly my discus seem to prefer this much lower light levels as well and now come out all the time with the light not seeming an issue at all.

Swords, anubias and java ferns do not need much light. I'm growing those plus toninas, a few limnophilias, a few lugwigias, some polygonums, about 5-6 different crypts, and some hygrophilias, some of which are considered fairly "high light" plants, and all are doing great under only 1.8 watts/gal of T5 lighting. Plus with my discus now I've cut my fert regime to almost nothing yet my plants grow great with nitrate levels at 5-10ppm and phosphates measuring about 2-3ppm, mostly I'm guessing from the discus poop. "Au natural" fertilzing now! (I do dose micro-nutrients though using Tropica)

You can go MH but be sure to give the discus some "shade" and be ready not to see them in their colorful glory much as they will likely not come out too much. But frankly for those plants that's much more light than is needed.

[exv152]

You may need the MH just because the tank is a staggering 28" high. The other thing is you may find 86ºF may be a bit too warm for most plants. As for the discus, well they'll probably let you know if the lights are too bright by hiding and not eating as much. My two cents.

[rich815]

You may need the MH just because the tank is a staggering 28" high. The other thing is you may find 86ºF may be a bit too warm for most plants. As for the discus, well they'll probably let you know if the lights are too bright by hiding and not eating as much. My two cents.

While I cannot speak for 86ºF, I grow a lot of plants at 84/85ºF with no issues. In this link I list out which ones, if anyone cares to see:

http://www.plantedtank.net/forums/fish/94844-discus-tank-suggestions.html#13

.

[exv152]

Hey Rich, thanks for the info. That's a really nice tank you have there!

I'm just curious, what kind of lighting do you have on that system, and do you turn the CO2 off at night?

[rich815]

Hey Rich, thanks for the info. That's a really nice tank you have there!

I'm just curious, what kind of lighting do you have on that system, and do you turn the CO2 off at night?

Hi Eric,

Thanks. The lighting is a Hagen GLO T5 HO system with 2x54W 48" T5 HO bulbs. One is a LifeGLO bulb (6700k) and one is a PowerGLO bulb (18000k). Lights on for 5 hours in the morning (6:30-11:30) and 5 hours in late aft' to evening (5pm to 10pm). CO2 goes on 1 hour before lights on and CO2 goes off half hour before lights go off.

[wunroch]

Verdict is in. MY discus do not like metal halides. I have a 3 bulb 175 Fixture. I left 1 bulb on and the other 2 off. The discus immediately stayed in the shadier side of the tank 99% of the time. When I turned 1 bulb on the shady side and turned bulbs off on the side that had been lighted they reversed sides. Halide lighting appears to annoy them. They are sluggish in the slight and also fail to show the colors. Bottom line is that I have order a set of 2 4 bulb 39 watt 5 fixtures with flourescents. Hopefully they will be happy in that lighting