Is It Possible To Have Too Much Light Intensity?

[csauer52]

My Setup:

150 Gallon Display
30 Gallon sump
SRO XP-3000SSS In sump skimmer
TLF-550 Phosban Reactor (GFO/AC mix)
Current USA 72" HQI/T5 Combo
3 X 250W HQI - 10K
8 X 39W VHO T5 - 460nm
Total Watts = 1062

T5's run for 10 hours a day
HQI's run for 6 hours a day

Tank Parms:
Temp: 76 - 79 (76 at night, slowly rises to 79 during photo period)
Amm: 0
Nitrite: 0
Nitrate: 0
SG: 1.026
dkH: 8.8 (drifts down to 8 over night, need to dose 30ml bionic daily)
Calc: 440
Mg: 1350
pH: 8.1 - 8.25

10% water changes once a week.

This tank will be predominantly SPS with a few LPS once fully stocked. No softies will go in this tank.

As of 3 days ago, my photo period used to be 12 hours actinics & 8 hours HQI. I just turned it down to 8 & 6 as once I began stocking, several SPS have either bleached or are showing signs of fading. To be honest, I know Alk swings can contribute to bleaching and admittedly, I wasn't testing Alk as I had thought the water changes would keep things in line. Alas, when I tested last weekend Alk was sitting at 7 so I knew I needed to begin dosing Bionic and have been dosing/testing since.

So far the bleached corals aren't showing any signs of coloring back up but they're not dead as the polyps still have color. Can I possibly have too much light? I don't have a PAR meter so no way to measure and obtain exact data.

I'm interested in hearing your thoughts on this.

Thanks!

Chris

 

[epicurus84]

Short answer is no, you cannot have to much light. However changing the amount of light or the color can cause the same problems.

 

[Alex T.]

Well, a 7 dKH is nothing bad. You'll find many successful reef tanks run in the 7 - 8 range. It's actually closer to NSW than most reef tanks that run 9 or 10.

Two things that jump out at me...

1. Your skimmer is pretty large for the system. I run the SRO XP 2000 on my 150 SPS tank and it's more than enough. I use to run a large downdraft skimmer and could pull a gallon of skimmate per week in my 150 gallon SPS tank. Once the tank got too clean my corals faded a bit. The skimmer was rated for 3 times my tank volume so I switched it out and things are better. Plus, it doesn't wait for critical mass of pollution before it starts skimming like my oversized downdraft did.

2. 10k 250 HQI are powerful bulbs...even on crappy ballasts. Many PAR readings of 250 watt 10k's are higher than 400 watt 14k readings. I would definitely expect some bleaching without shaded, sandbed introduction of SPS corals or raising the lights a few inches and lowering photoperiod.

Your parameters seem fine as long as they're steady. All that being said, just slowly introduce them to your light. You may need to keep many LPS in the periphery of the tank and partially shaded under some strategically placed rocks.

 

[csauer52]

1. Your skimmer is pretty large for the system. I run the SRO XP 2000 on my 150 SPS tank and it's more than enough.

Well, I was running an ASM G2 prior to this and no matter what, I always had algae on the back glass. I could never seem to get rid of it so I figured it was that the ASM wasn't getting enough garbage out of the water column. As a result, I upgraded to the RO as it was rated up to 300 and I like to feed my fish every day.

2. 10k 250 HQI are powerful bulbs...even on crappy ballasts. Many PAR readings of 250 watt 10k's are higher than 400 watt 14k readings.

Your parameters seem fine as long as they're steady. All that being said, just slowly introduce them to your light. You may need to keep many LPS in the periphery of the tank and partially shaded under some strategically placed rocks.

I wasn't aware the HQI's were that powerful. That might explain my issues. The funny thing is that some corals seem fine under these lights and some look like it's too much. For example, my ORA plum crazy looks awesome yet the red planet is faded big time. The green base is completely washed out at this point and they're at the same height in the tank.

Very strange...

Also, the glass from the HQI's is 6.5" above the water line and the reed planet is 15" below the surface. I also have a favia in the sand which is 26" below the surface which has also faded. Is there anything I should do or just wait for them to become acclimated to this lighting?

 

[Alex T.]

If they're bleaching, you could screen the area above them or lower them to the sand bed until they recover and slowly move them up. That's what I did with mine when they started showing some light related stress. A shortened photoperiod with the halides is also not a bad idea for a while.

As for lighting, I always defer to the master. Here's Sanjay Joshi's lighting guide for 10k Spectrum bulbs in all wattage bulb and ballast combinations that he's tested. I think you'll be surprised at how high some of the 250 watt Double Ended 10k bulbs are in PPFD.

http://www.manhattanreefs.com/lighting

 

[csauer52]

PPFD? I'm not familiar with that aconym.

Thanks for the links. I had a look but I really don't know how to read the data. What should I be looking at?

 

[csauer52]

Here are some images too so you can see what I'm saying. They were taken with my Android phone so they're not great.

 

[csauer52]

The first is the Red Planet. You can see how washed out it is but the other acros look pretty good and are growing great.

 

[csauer52]

And here's a bleached Monti of sorts...

This guy is almost on the bottom of the tank. At least 22" below the water surface.

 

[29reef]

With the amount of stuff growing on the rocks it could easily be caused by water quality. I would say you can easily remove 1/2 of the T12 actinics. I would try keeping your water stable and raise your alk to 9 slowly. Are you using carbon dosing? GFO? Zeo?

You have what looks like a lot of bacterial growth on the rocks, but it could also be algae. How do you measure phosphate? How long have you had SPS in this tank?

 

[29reef]

With the amount of stuff growing on the rocks it could easily be caused by water quality. I would say you can easily remove 1/2 of the T12 actinics. I would try keeping your water stable and raise your alk to 9 slowly. Are you using carbon dosing? GFO? Zeo?

You have what looks like a lot of bacterial growth on the rocks, but it could also be algae. How do you measure phosphate? How long have you had SPS in this tank?

 

[csauer52]

With the amount of stuff growing on the rocks it could easily be caused by water quality. I would say you can easily remove 1/2 of the T12 actinics. I would try keeping your water stable and raise your alk to 9 slowly. Are you using carbon dosing? GFO? Zeo?

You have what looks like a lot of bacterial growth on the rocks, but it could also be algae. How do you measure phosphate? How long have you had SPS in this tank?

Hi Brian. I'm fairly certain the growth on the rocks is a diatom bloom. I recently changed filters in my RO/DI unit and had a massive bloom when I did the first water change afterwards. I need to make a mental note to run a gallon or two into a bucket next time prior to mixing up a batch of salt.

I run GFO & AC in a TLF 550 reactor in addition to a chemi-pure sponge. I don't know what Zeo is.

I have had SPS in the tank for two months, it's still fairly new at this point. My plan was to stock a few corals and see how they did for a while before adding anything else to the tank. The corraline is starting to come in nicely all over the tank and several of the corals are showing very nice color/growth.

I use a Salilfert kit to measure P04 and it reads 0 but I don't know if I trust the kit.

 

[xcorallusx]

maybe its your flow?

 

[csauer52]

maybe its your flow?

I think I have pretty good flow. I'm turning over 50X tank volume.

 

[csauer52]

So I lowered the photo period on the HQI's to 5 hours/day. I'll leave it here for a while and see what happens with the bleaching.

 

[Dog boy Dave]

Dont fool yourself. You got a water quality issue. Your lights are fine.

 

[csauer52]

Dont fool yourself. You got a water quality issue. Your lights are fine.

Thanks Dave. Well if that;s the case, it's not detectable using standard test kits so I have no idea what it is. Thinking I should change my RO membrane as well. I was making some top off water yesterday and my TDS meter was reading 002 even after all my pre-filters were just recently changed. Wondering if I'm getting phosphates/silicates in with my RO water?

:hmm6:

 

[karsseboom]

All that algae is consuming your p04 and giving you a false reading.

 

[csauer52]

All that algae is consuming your p04 and giving you a false reading.

Now that certainly sounds feasible. I'm beginning to wonder if my water supplly is the culprit. To be honest, I've always had some sort of algae in my tanks throughout the years (especially on the back glass) and I've never been a slacker when it comes to maintenance/water changes. The only thing I can think of is that my water supply is tainted with high phosphate levels or silicates. I started running Pura Phos non-stop in my reactor. I guess it will ljust take time to eliminate whatever is in the tank.