chucelli

I had an imperator angel that ate sponges. Though it eventially started eating other things as well... -R

IME, STN and RTN are some of the most difficult things to find causation for... Sometimes, there just may be nothing you can do. I wouldn't be able to begin to suggest what may be causing your STN, but the best advice I would have is not to take any drastic measures, as the already weakened corals may just "kick the bucket". Are these frags or colonies fairly new? -R

You can lower PH by adding seltzer or soda water, or vinegar in extreme cases. I don't think your PH is causing any issues though. Whatever you do, do it slow. I find that many times, when we discover an issue, the proposed remedy is applied too fast, causing bigger problems. -Robert

I think 40˚ optics is a good idea simply because you have more options when it comes to intensity vs. coverage. All you have to do is adjust mount height to acquire desired intensity/coverage. The best thing to do would be to get some PAR readings from these lamps. Seeing that it is passively cooled, my bet is that they are running at 350mA, a very conservative setting to prevent overheating. Just for reference (from Cree's datasheets): XR-E outputs in lumens: 107 lum@350mA 160 lum@700mA 33% increase in output 210 lum@1000mA 51% increase in output -R

Rob, do you know at what current these PAR38 bulbs are driven? -R

Lenses or optics may cut light output, but the amount you will be gaining more than offset the relatively negligible loss. I would recommend a fixture with some type of optics, since the amount of light wasted (bleeding out the sides) without optics are not trivial. I would choose 40˚ for high mount (>4' from water surface, and 60˚ of anything less than that. 80˚ if you are more concerned with coverage over intensity. Also keep in mind, that comparing these LEDs to MH is not as easy as deciding how many you will need. With 40˚ optics and lower mount height, you can easily surpass any 400w MH output in a given area and end up bleaching your corals. I suggest borrowing the club PAR meter and running some tests. -Robert

was this a newly acquired specimen? I've seen this happen as far as two weeks into acquisition due to differences in specific gravity. -R

you will end up with little chunks of acrylic on the blade and not very much cut. -R

This article may be of interest to you. -R

I think it's pretty cool to have some shadows... but that's just me. Perhaps you could use 1 400w bulb on a track. -R

I think it's certainly worth a try.. I seem to recall something in a biology paper that mentioned intensity was more important than the duration, as long as it was past a certain (x) amount. (x) is what I don't remember exactly... but I know that corals can reach photosaturation in ≈4 hours. So for example, it you were to blast them with intense light for 4 hours straight and then darkness for the next 20 hours, they would still be able to generate enough sugars through photosynthesis. -Robert

I thought it was just us.. we've been discovering stink bugs in our house as well. I don't ever remember seeing any insects in past winters... I'm surprised they can get in with all our windows sealed in the winter. -R

uploaded a video. Color is a bit washed, but you can see what the light looks like on moving water... -R

I wouldn't do anything drastic. Rust alone won't really harm your tank especially in such a short period of time. I knew someone who had been running a tank for a few years before discovering a rusty razor blade at the bottom of his skimmer... Everything in his tank was fine and sps growing... I would just do water changes and run carbon according to your regular schedule. -R

I used to run 20kand 10k MH only and IME, others who supplement with heavy blues (VHO, T5) have better coral colors. Not just appearance under lighting, but actual pigments. -R

Jim, I could try to make it to the next social on the 23rd at the zoo. If we could arrange to have it over a tank, even better. It is hard to say what color conventional lighting they compare to. These definitely have a blue bias to them, however, they do not mute the colors like 20k lamps tend to do. The appearance of the end color can also be adjusted though different optics combinations. Lastly, the LED blue/white ratio can be changed to further change light color. However, the 50/50 ratio seems the most commonly used ratio, and I would say has a proven track record for excellent coral growth and color. "soundwave" or "menthol" are two RC names which come to mind when I think of good coral coloration (both use 50/50 ratio). -R

nice lights! The best way IMO to get corals is from folks here. Lots of friendly people. It's like shopping at a flea market except better. It also takes some strain away from wild corals. -Robert

I think by turning off the skimmer (momentarily) you are allowing MB7 to stay in the water long enough to do its thing. I'm sure keeping the skimmer on works as well, but you are probably removing some of what you just added. Any major metabolic action in a closed environment will result in fast depletion of oxygen, which will cause PH to drop. Leaving the skimmer off for prolonged periods during any type of bacterial or microbe dosing is a sure way to kill all your fish. -R

fry_school101, The fans keep the layer of heated air from staying around the heatsink. This, in turn helps the heatsink maintain ambient air temperatures. If the heatsink is kept cool, the LED junction temperature will also be kept within specs. During the testing phase, heatsink temperatures did not get anywhere close to the max spec'd 80˚C. However, I did not have any accurate means to measure junction temperatures, so my design had to be conservative. Any air movement through the heatsink fins is enough to keep the heatsink at ambient air temperatures (≈71˚F or 22˚C). Without the fans, certain parts of the heatsink measured at ≈60˚C. Also, since operating temperatures have a direct impact on LED light output, I wanted to make sure light output was never compromised, as any decrease in output would most likely not be detected by our eyes. In short, the fans are doing alot in cooling the LEDs. zygote2k, It is possible to mount these as close as you want. Do a search on RC or Youtube for "soundwave's" LED build. He has them mounted inside a canopy. Although I would definitely recommend the use of some kind of splash guard for the lights if that is your plan. Also the use of optics would have to reconsidered. Perhaps 80˚ optics could be used, but most likely at that mount distance, the best result will be no optics. Although IMO, no optics means lots of light is wasted (refer to my PAR measurements table). These examples can be seen clearly when you see a room completely lit up vs the same fixture lighting up a specific area (tank) only. Doug, I don't know what a facebook bump is, but it sounds good. Thanks, -Robert

Yes, I just dumped it into the display. -R

I used it to help cycle a new tank. I just turn the skimmer off, per instructions, and add it to an area of high flow. You will see stringy brown growths in low flow areas the very next day if it is over-dosed. Otherwise it worked very well for me. You can definitely see the difference. Water is clearer. The problem is, I noticed as soon as you stop using it, water quality reverts back to pre-dose state. Because of that, I don't think MB7 contains self sustaining bacterial cultures. Therefore, you can't use it to seed bacterial populations. -Robert

For anyone with technical questions, or any other questions, including total cost of materials, technical specs, please visit: http://www.reefaddicts.com/ This is Marc Levenson's new site (Jan2010), which features articles and other useful information for reefers. There is an article on my LED pendent currently on the front page. It contains most relevant information discussed in this and other threads, including the first prototype build and some test documentation. Thanks, -Robert

George, I don't have much time to build these for people as is, so I can't commit to any custom work outside of the templates and tooling required to make these Gen2 pendents. However, I am interested in what you may have in mind. PM me and we can discuss further. davidm, The LED spacing is 1.5" from emitter center to center. I never considered using the "glue" you speak of. It would have actually saved me much time and money if I had used the "glue". Instead, I chose to mount all LEDs with stainless steel screws so that they may be removed in the future for upgrades or repair. Also, mounting with screws allows me to use high quality thermal paste, which is a much better heat conductor than the "glue". That "glue" you are referring to, is actually a thermal epoxy. Once cured, it is very difficult to remove. It is also not the best heat conductor. I'm not sure I completely understand your last question, but hopefully, this will answer that question... All LEDs on my pendents have secondary optics which gather and focus light. Different angle optics can be used to suit individual needs, ie. mount hight, light intensity, etc... Different optic combinations can also be used to further customize light quality, including color (for a more white or more blue appearance). Pendents can also be run without optics for more traditional light output at the expense of intensity and reach. I would not recommend running without optics, since much light is wasted when run without optics. Steve and Laura, prices for these pendents were posted in the "for sale" section as requested by the moderators a while ago. I'm not sure where that thread is now, but you guys can PM me if you are interested. Thanks, -Robert

Some updates on coral color: Here is a small brown acro colony I got from David (coralhind) a while ago. It has always been dark brown, until now: small frag in the center (developed tips within the past week): same brown acro species mounted on frag tiles (i did not frag these, my hippo did) : 1st and 2nd from left: The 1st greenish one has lived close to the center bottom of the display for about 3 weeks. The 2nd from left has been mounted and placed in same location for about a week. Mother colony: still largely dark brown (in low light area), but seems to have developed more colorful tips: purple acro center right also lightening (same coral far left of pic in lower light area): another FTS from couple days ago: -Robert