OHM Optics Install Guide
ReefBreeders / Installation Guide
OHM Optics Ocular Holo Matrix
One optic covers one full LED matrix. Swapping them changes the shape of the beam, which changes how wide the light spreads and how deep it drives coral growth. Three spreads are available, and you can mix them within a single fixture.
The three optics
Every Meridian ships with Balance fitted. Focus and Encompass sit either side of it, one tighter and one wider.
45°
OHM Focus
The tightest beam. Concentrates output into a smaller footprint and carries usable light furthest down, up to about 48 inches (120 cm). The optic to run on deep tanks, or wherever corals sit low in the water. Ships fitted on Edge bars.
90°
OHM Balance
The standard optic. An even, well blended spread that reaches up to about 36 inches (90 cm) down, which covers the great majority of reef tanks. If you are not sure which to run, this is the one.
110°
OHM Encompass
The widest beam. Pushes the footprint further front to back and softens shadowing between colonies, reaching up to about 24 inches (60 cm) down. Suits wider or shallower tanks, and setups where the fixture mounts low.
Telling them apart
Out of the box, all three optics look virtually identical. Each one is marked with its spread.
| Optic | Marking | Beam |
|---|---|---|
| OHM Focus | 45 | Tightest |
| OHM Balance | 90 | Standard |
| OHM Encompass | 110 | Widest |
Coverage by fixture
Footprint is given as length by front-to-back. All three optics will grow SPS. What changes between them is how deep the tank can be, so choose on water depth rather than on what you keep.
| Fixture | Focustanks up to 48 in / 120 cm | Balancetanks up to 36 in / 90 cm | Encompasstanks up to 24 in / 60 cm |
|---|---|---|---|
| Meridian 11 | 16 × 16 in40 × 40 cm | 24 × 24 in60 × 60 cm | 30 × 30 in75 × 75 cm |
| Meridian 24 | 24 × 24 in60 × 60 cm | 36 × 24 in90 × 60 cm | 36 × 30 in90 × 75 cm |
| Meridian 35 | 36 × 24 in90 × 60 cm | 48 × 24 in120 × 60 cm | 48 × 30 in120 × 75 cm |
| Meridian 45 | 48 × 24 in120 × 60 cm | 60 × 24 in150 × 60 cm | 60 × 30 in150 × 75 cm |
| Meridian 63 | 60 × 24 in150 × 60 cm | 72 × 24 in185 × 60 cm | 72 × 30 in185 × 75 cm |
| Max coral growth depth | 48 in120 cm | 36 in90 cm | 24 in60 cm |
How many optics your fixture takes
One optic covers one LED matrix, and each step up in fixture size adds another matrix.
| Fixture | LED matrices | Optics needed |
|---|---|---|
| Meridian 11 | 1 | 1 |
| Meridian 24 | 2 | 2 |
| Meridian 35 | 3 | 3 |
| Meridian 45 | 4 | 4 |
| Meridian 63 | 5 | 5 |
Swapping the optics
You will need a number 2 Phillips screwdriver and a soft surface to work on. Allow 10 to 30 minutes depending on the size of your light, roughly 10 for a Meridian 11 and 30 for a 63, and take it slowly.
-
Unplug and set up your workspace
Unplug the light from power and take it off the aquarium. Lay it on a table with a soft covering, a drop cloth or silicone mat, facing upwards.
-
Remove the bottom panel screws
Undo the screws holding the bottom panel of the case on. The outer screws have coarse threads and the middle screws have fine threads, so keep the two groups separate as you set them aside. Mixing them up on reassembly is the easiest way to damage a thread.
-
Lift off the bottom panel
With all the screws out, remove the bottom aluminum panel and set it somewhere safe. The LED matrices and their optics are now accessible.
-
Remove the old optics
Each LED matrix has one optic held on by four screws. Undo all four, then flip the optic over so the screws drop out onto the table rather than into the fixture. Each screw has a nylon washer on it. Make sure those stay with the screws.
-
Seat the new optics
Set each new optic in place, aligned with the LEDs on the board. Most optics have two small positioning feet to help you line them up. These sometimes break off in transit, which is fine, as they are only for reference.
Do not force an optic into place. It should sit down fully and squarely on its own. Forcing one can break an LED diode, and that damage is not covered under warranty. -
Screw the optics down
Drop the four screws into the screw slots in each optic and tighten them in an X pattern, working across the diagonal rather than around the edge. Tighten to one-finger tight, no more.
-
Refit the bottom panel
Put the bottom cover back on and start the middle screws first, which aligns the plate correctly, then fit the outer screws. Remember which group is which.
-
Reinstall and power up
Return the light to the aquarium and plug it back in.
Mixing optics in one fixture
Because each optic covers its own matrix, you can run different spreads across a single light and tune the beam to your aquascape rather than the other way around.
Worked example
A tall rock structure in the middle
On a Meridian 35 with three matrices, a central tower makes that part of the tank effectively shallow while the sides stay deep.
Run Balance or Encompass over the center to spread light across the structure, and Focus on the two outer matrices to punch deeper into the side areas.
Use caution
Focus over shallow areas
Focus concentrates output, so placing it above a shallow section of the tank produces very high PAR at the top of the rockwork.
If you are aiming Focus at a raised area, plan on dialing back intensity and acclimating corals gradually.
Cleaning your optics
Salt creep builds up inside optics over time and dims output. Whenever you have the fixture open is a good moment to clean the set you are taking off.
-
Soak
Fill a small bucket with RODI water, put the optics in, and swish them around until they all sink.
-
Shake out
Take them out one at a time, shake the water out, and spread them evenly over a dry towel.
-
Dry completely
Give them several days to dry fully before they go back in or into storage. Do not reinstall an optic that is still damp.
Common questions
The things people ask us most about OHM optics.
How do I tell which optic is which once it is out of the box?
They look virtually identical, so each one is marked with its spread around the rim: 45 for Focus, 90 for Balance and 110 for Encompass. The lettering is small, raised and clear, so hold the optic against a dark background and use a flashlight at an angle to read it.
What does OHM stand for?
Ocular Holo Matrix. A matrix is one group of 24 LEDs, spread out across the board rather than clustered tightly together. One optic is a single panel covering all 24 of them, rather than an individual lens sitting over each diode.
How many optics do I need for my light?
One per LED matrix, and each fixture size adds a matrix. The Meridian 11 takes one, the 24 takes two, the 35 three, the 45 four and the 63 five.
Can I mix different optics in one fixture?
Yes, and it is one of the more useful things you can do with them. Each optic covers its own matrix independently, so you can spread light over a shallow central structure and punch deeper at the ends. Just be careful about putting Focus over a shallow area, since the PAR there will be very high.
Does opening the light void my warranty?
No. Changing optics is a supported procedure. What is not covered is damage you cause in the process, the two common ones being stripped threads in the heat sink from using a power driver, and broken LED diodes from forcing an optic into place.
Why do the screws have to stay in separate groups?
The outer screws on the bottom panel have coarse threads and the middle ones have fine threads. Putting a fine screw into a coarse hole, or the reverse, will damage the thread in the aluminum. Keep the two groups apart while the light is open.
One of the little feet snapped off my optic. Is it ruined?
No. The two positioning feet are alignment aids only and sometimes break off in transit. An optic missing one or both still seats and performs normally. Just take a little more care lining it up with the LEDs.
Which optic should I choose?
Start with the depth of your tank, measured top to bottom. Encompass carries usable light down to about 24 inches (60 cm), Balance up to about 36 inches (90 cm), and Focus up to about 48 inches (120 cm). Balance covers most tanks and is what your fixture ships with. From there, go wider to Encompass on a shallow or wide tank, or where the fixture mounts low, and go tighter to Focus on a deep tank or where corals sit low in the water. The coverage table in section 03 gives the footprint for your fixture size.