Level of light for different porites?

[dendro982]

I have green and brown porites, likely Porites astreoides color morphs (but I could be mistaken), and the fine cocoa with milk color, likely Porites echinulata. While 3 brown porites are doing quite well with moderate lighting, what will be requirements of the green and cocoa porites?
They are doing worse, but the tank has elevated Mg for bryopsis treatment. Trying figuring the cause of bleaching, while the brown are OK.
Few months ago changed PC to MH, the same wattage, 70W at 6" distance, 14,000K.

[PSam]

IME, with good parameters, porites will grow anywhere - may not look as nice in lower light, but will do fine.

I've a large rock of porites that is brown if at the bottom of tank, but thrives right under light as well, staying brown overall but throwing out it's pink & green pigments if too close to the light. Also have Paletta's purple porites, which is a gorgeous purple w/ white polyps directly under light, but still does fine under lower light, just turns brown.

If they're bleaching, I'd look for something other than the light?

[dendro982]

These are Christmas tree rocks, actually, with worms. The fine cocoa colored was good under the same wattage PC. This is filter feeders tank. a lot of particulate matter, but no sediment on corals. NO3, PO4 are 0, but have bryopsis.

What I could think of:
- UV: may be MH (70W) requires covered tank - yesterday placed thin piece of Lucite (UV-protected carbonate plastic?) on the top of the tank.
- 1600ppm Mg, for the bryopsis treatment,
- may be dosing (top off, alkalinity and Ca additives) should be dripped in other place - return pump flow reflects from the tank wall nearby. Not a harmful force, as I can feel (150 gph Mini-Jet).
- Laminar flow, 300 gph total, including return pump, in 20g long tank. Wasn't in previous tank configuration, but now 6 Christmas tree rocks (1 is pavona, others - porites) are in the row, with not much space left.

This is cocoa colored, no becomes cold greyish:

Pvona nearby becomes lighter too, slowly, but has new growth. Birdsnest, stylopora, pocillopora, montipora and babies tridacnas are fine.

Green porites are not opening in full, relatively new coral:


Tank recently, 20L:


no powerhead at the right now - only return pump flow, directed on the wall.

Previous tank configurations:
In 10g all was very well (except bryopsis):


in 12g cube, laminar bottom to the top flow - too:


But after that I bought two more Xmas rocks, ad had to use the bigger tank.

May be hex will be better? Any other thoughts?
Thanks.

[Oldude]

This is cocoa colored, no becomes cold greyish:

In this picture there is a patch of porites next to the pavona that looks like it's been getting tagged. Pavona is aggressive and can send out some nasty sweepers. I would consider changing the flow pattern so it sends it's sweepers in the other direction.
With a closer look that piece almost looks more like hydnophora than pavona but tough to tell from the picture. Either way they are both aggressive while porites is quite passive. Do you run carbon?

[dendro982]

Yes, I run carbon, but changing it maybe once in two weeks. What should be distance from other corals for pavona?

This is a baby, that big pavina dropped - it already started to grow:


Big pavona rock:


They are pretty close together - I hadn't problem with that for porites:



There is one bald place on the cocoa porites - from the pavona side:


But not - at the place, next to it:


Green porites are very close to pavona - 3/4" maybe, no baldening.

Any thoughts?
Thanks.

[Oldude]

Yep, definately Pavona. It could be the flow pattern allows the sweepers to hit in that spot or perhaps it's not the problem. I think one issue is that the different types of porites have different light requirements. IME the yellow & purple like strong lighting and the brown & green prefer med or even low light so you may have to rearrange the scape a bit to accomidate this.

[dendro982]

How long are pavona swipers? I had seen only 3/8" or so.

Your opinion on minimal lighting for them, sufficient for a growth?

I thought, that mine is close to a minimum - 70W and direct sunlight from the southern window.
But - one of the brown porites was few months even under 54W, and in far shaded corner - survived, only grow the longer polyps.

Totally unfamiliar with green ones.
All I could find - abstract and full text of the research article on the content of the UF-protective substances in brown and green morphs of the Caribbean coral Porites astreoides.
If mine are P. astreoides (and they look similar), the green grows in the wild in shallower waters and has more UV-protection.

But my light is not strong, the distance is 6", 2 of them - water. Was uncovered tank - now has thin UV-protected Lucite on the top. Brown one, next to the green - is good and even grows.
Are actinic lights necessary in addition to the 14,000K MH? I don't have them now.

What else should I try: set old PC light, same wattage? Started to lower Mg levels too. Raise or lower temperature? Now is 77F.
Ah, have also aluminum-based phosphate remover. No problems with other sps, can even change it on iron-based, but had read, that the presence of iron may provoke or cause pinched mantle disease for clams - I have small Tridacnas.

Any particularities of porites keeping, comparing to other sps?