Help me decide on how many LED arrays I should add

[HM3105]

Hey all,

I'm building a new hybrid LED rig and I'm kind of going back and forth on the number of LED arrays to use.

I am planning on using the BlueAcro arrays, what I'm undecided on is how many to use. I've narrowed it down to the following choices.

3 Mega4z 20K
OR
4 Half Mega 18K

These will be paired with TWO 54w T5 Actinic.

The tanks' dimemsions are 48x30x18 (LxWxH).

Because of how wide the tank is, it seems like the high power of the Mega arrays will be useful to maximize the real estate available.

My goal, is this is probably silly, but I would like to be able to push 400 par down the middle of the light and around 100 on the sand near the edges of the tank.

Thoughts?

 

[mcarroll]

No links or descriptions for the LED's you're talking about and only the 20K's show up on their website of the two models you mentioned. Providing more info (if you have it) would be helpful.

From what I can tell from their website, those are too small for just 3 or 4 to be of much use in your design. If you want to use them I'd guess a LOT more would be needed. Do they have lenses? How many watts will they consume in their final installation? If you're a fan of that company and just want to use them, you'll need the answers to those questions if you want to use them well. Holler back if you have any of that info already. If not, I think I'd look elsewhere.

Folks use 4-bulb systems to light a tank half that width. I think you're going to want more emitters whether you're talking about T5 tubes or LED's.

If you like the uniform light from T5's, I'd be looking at an LED strip system like Current's Orbit Marine Pro...2 or 3 x 48" strips, or optionally 4 x 36" strips run perpendicularly. No need for T5's, but you still get great coverage and a quality system.

Plain full length strips (either 36" or 48", whichever) are available from lots of vendors, including other options from CurrentUSA, Hamilton Technologies' Kona Sun VHO strips, etc.

If you want to suspend the light over the tank by some distance, the Orbit Marine Pro is probably you're single best bet because of its use of 60º lenses – most strips are un-lensed. With wider lenses (or T5's), if you try to raise the light up you almost immediately start wasting energy by removing light from the tank and lighting up the room more. May or may not bother you, but it's definitely a waste, so something to think about.

 

[HM3105]

No links or descriptions for the LED's you're talking about and only the 20K's show up on their website of the two models you mentioned. Providing more info (if you have it) would be helpful.

From what I can tell from their website, those are too small for just 3 or 4 to be of much use in your design. If you want to use them I'd guess a LOT more would be needed. Do they have lenses? How many watts will they consume in their final installation? If you're a fan of that company and just want to use them, you'll need the answers to those questions if you want to use them well. Holler back if you have any of that info already. If not, I think I'd look elsewhere.

Folks use 4-bulb systems to light a tank half that width. I think you're going to want more emitters whether you're talking about T5 tubes or LED's.

If you like the uniform light from T5's, I'd be looking at an LED strip system like Current's Orbit Marine Pro...2 or 3 x 48" strips, or optionally 4 x 36" strips run perpendicularly. No need for T5's, but you still get great coverage and a quality system.

Plain full length strips (either 36" or 48", whichever) are available from lots of vendors, including other options from CurrentUSA, Hamilton Technologies' Kona Sun VHO strips, etc.

If you want to suspend the light over the tank by some distance, the Orbit Marine Pro is probably you're single best bet because of its use of 60º lenses – most strips are un-lensed. With wider lenses (or T5's), if you try to raise the light up you almost immediately start wasting energy by removing light from the tank and lighting up the room more. May or may not bother you, but it's definitely a waste, so something to think about.

Ok my fault, here are the links.

The information is here: https://blueacro.com/acrostar/products

The PAR map I got for this light provided a range of values and I took the lowest which is shown below:

Full Mega:
On center: ~470 PAR
12" from center ~52 PAR

Half Mega:
On center: ~260 PAR
12" from center ~30 PAR

12" from center = 24" by 24" square with the LED centered. That means I am essentially trying to get the T5 to contribute ~50 PAR 8" off center to a depth of 18" ex. sand.

Here are my two proposed layouts, I'm re-purposing an old MH/T5 combo.
3 Full Megas

6 Half Megas (changed from OP)

I'm not sure what the PAR drop is for T5s, I wasn't able to find anything that was super helpful in the various measurement threads as they tend to measure from the center and not off center. Perhaps that is not relevant given T5's project from all angles but I suspect it is.

 

[mcarroll]

Dimensions
Is the tank 30" high or 30" wide? Your OP says the later, but your diagrams say the former.

If it's a wide, shallow tank as I originally thought, then you'll want to have these strips about 8" off the water to get coverage across that whole 30" of space. Keep in mind that the light at the edges of that projection are going to be much weaker than under the strip. (How are you going to make sure these things stay cool?)

On the other hand, if you have a 48x18x30H" deep tank that you want to light for corals, I'd scrap the whole plan in favor of anything with lenses. One or two 48" Orbit Marine Pro's, for example. Kessil narrow-beams (though you'd need several). Of the top of my head, that might be it...the rest use wider lenses or (like the kessil wide-beams) no lenses at all.

Regardless of brand, I'd stick with strip lights in order to keep the even lighting you might be used to from the T5's. You'll probably want four to six plane-jane LED strips. (Double that for the wider tank.) You can get blue and white strips separately, or get combined blue+white strips...either or, won't matter too much.

Measure Your Light
By all means you need to have a light meter, or you'll be unlikely to end up with satisfactory results.

At minimum get a lux meter app. For example "galactica luxmeter" for IOS. It's free, and there are many to choose from, so there's no excuse for not having something like this at a minimum!

A $15 handheld meter is better and safer to use around your tank than your smartphone. For example the "LX-1010B" that I use.

Expert Tip: If you can borrow a PAR meter, you can calibrate your lux meter to your lights with it. This gives you an accurate conversion factor to convert any future lux readings to PAR if you need to share them with someone, for example. Other than that, you can definitely get by without a PAR meter, but it's cool if you have one!

 

[HM3105]

Dimensions
Is the tank 30" high or 30" wide? Your OP says the later, but your diagrams say the former.

If it's a wide, shallow tank as I originally thought, then you'll want to have these strips about 8" off the water to get coverage across that whole 30" of space. Keep in mind that the light at the edges of that projection are going to be much weaker than under the strip. (How are you going to make sure these things stay cool?)

On the other hand, if you have a 48x18x30H" deep tank that you want to light for corals, I'd scrap the whole plan in favor of anything with lenses. One or two 48" Orbit Marine Pro's, for example. Kessil narrow-beams (though you'd need several). Of the top of my head, that might be it...the rest use wider lenses or (like the kessil wide-beams) no lenses at all.

Regardless of brand, I'd stick with strip lights in order to keep the even lighting you might be used to from the T5's. You'll probably want four to six plane-jane LED strips. (Double that for the wider tank.) You can get blue and white strips separately, or get combined blue+white strips...either or, won't matter too much.

Measure Your Light
By all means you need to have a light meter, or you'll be unlikely to end up with satisfactory results.

At minimum get a lux meter app. For example "galactica luxmeter" for IOS. It's free, and there are many to choose from, so there's no excuse for not having something like this at a minimum!

A $15 handheld meter is better and safer to use around your tank than your smartphone. For example the "LX-1010B" that I use.

Expert Tip: If you can borrow a PAR meter, you can calibrate your lux meter to your lights with it. This gives you an accurate conversion factor to convert any future lux readings to PAR if you need to share them with someone, for example. Other than that, you can definitely get by without a PAR meter, but it's cool if you have one!

It's 30 wide, 6-8 inches off the water surface doesn't bother me. That's where my LEDs are now.

The I'm trying to use the t5 to help with the shadowing most LEDs produce on SPS plus add to the PAR on the edges of the tank. Those are my goals with the t5.

For coolong, I'm putting a pair of 120mm fans in the case, it should keep everything cool....

 

[mcarroll]

I say if you don't like the shadowing effect, don't create it in the first place. Lots of reefers miss this point...as far as I can tell, the only reason is the popularity of spotlights. The problem with that is that I can't understand why spotlights became so popular. The whole situation doesn't make a lot of sense to me since so many people don't seem to like the light spotlights put out in such a fundamental way. LED strips seems to be discounted before they are even considered in service to this popularity....even though they don't produce that shadow effect.

If you're feeling invested in the T5's go ahead and use them, but I assure you they are an unnecessary expense and could safely be replaced with LED's.

I'm not sure I'd go for these rectangular pucks unless you want to effectively build a strip (or strips) of them to avoid the spotlighting/shadowing they will create. I doubt the 16" spacing you have planned will do it....similar lights need to be spaced closer, like 12" or less. Would you want to do this?

 

[HM3105]

I'm not sure I'd go for these rectangular pucks unless you want to effectively build a strip (or strips) of them to avoid the spotlighting/shadowing they will create. I doubt the 16" spacing you have planned will do it....similar lights need to be spaced closer, like 12" or less. Would you want to do this?

I wouldn't mind doing that but I would use the half mega pucks for that and use 5 running down the middle. The only goal I have is to achieve 400 PAR (if I desire) for a ~12" section of the tank.

The whole build is designed to avoid shadowing, while I understand the spot light vs. strip function, the BlueAcro pucks use a diffuser which is meant to help reduce shadowing. That is partly the reason I am intrigued by those pucks in the first place.

 

[mcarroll]

Certainly a worthy experiment! I hope you keep posting during the build and deployment – I am curious about the final result!

I just happen to not be a fan of T5 hybrids....(but I do like spot-type lights OK, which might be surprising....I just understand why other folks don't)....no matter though!!

I like the idea of using the half-power pucks at a much higher frequency.

You may already, but I think I'd have two more strips (and related supplies) than you think you need. If it turns out to be too many, you have fodder for another project or maybe you'd return them. But if you don't like the shading "as planned" an additional set could be crucial, and would at least allow you to experiment with more of them. If budget allows it seems like a good idea. Also from a having-spares point of view.

I would suggest being prepared with at least a handheld lux meter during layout so you can be empirical about blending them with each other and with the T5's. At $15, it's a great investment if you're a DIY'er....which you are. I think every reefer should have one of these (at least).

 

[gus6464]

6 full mega with Ledil Angela-W on 2 row setup with 3 per row. Hang 12-14 inches from top of tank. You have to ask blueacro what's the ledil mount for their stuff. I think it's bridgelux vero 18 mount but better to verify.

Angela's are no joke.