No Coral Growth

[teddscau]

Okay, so long story short, only our montipora is experiencing skeletal growth. Our dendrophyllia, balanophyllia, sun coral, blasto, pocillopora, hammer, two different species of acan, and acros are experiencing zero/minimal skeletal growth. We kept thinking it might be due to inadequate lighting, but that doesn't make sense since NPS corals don't require light (plus they get fed several times a week). Pocillopora's supposed to grow like a weed, but it's grown MAYBE 1 cm in the past 3 years.

pH 7.85
KH 9.5
Salt 35
Calcium 440ish
Magnesium 1600
Nitrates 8 (was up to 32-64)
Phosphates 0.08
Temperature 77°F
Instant Ocean Reef Crystals
4 Kessil A360x
Reef Roids every four days.
25% weekly water changes to get nitrates down. We're now doing 10%–20% water changes twice a month, depending on nitrate levels.

Our softies are doing fine, but then again, they're softies (mushrooms, palys, zoas, leathers). Our red plate montipora is growing the fastest, the rainbow montipora is growing at an okay rate (colouration sucks, so we moved part of the colony closer to the lights), there's some sort of encrusting yellow monti with little branches near the surface which grows fairly well, our forest fire digi which is growing fairly slowly, and finally our beach bum which probably isn't growing at all.

We also have some meat corals who are nice and plump. Our dendro only had seven heads when we got it, but now it has around 50 (there's only been new polyps growing, no branching whatsoever, so now it's just a deformed blob filled with polyps).

[bertoni]

Those parameters are reasonable. I might try to lower the phosphate level to 0.03 ppm or so, but it's hard to know whether that will help. Another wild guess would be some sort of allelopathy (chemical warfare). Are you running activated carbon or ozone? Are the colors okay?

[teddscau]

I don't think we have any activated carbon in there... I'll have to ask my dad. As for the colours... I don't think they're quite as colourful as they could be (some are a touch brown), but the ones that we're struggling with colourwise were completely bleached when we got them (they came with our old tank and were barely alive). Others (rainbow monti, for example) were extremely colourful when we bought them from coral shows, but as soon as they were bagged they lost their colour/turned brown/turned rust coloured, and refused to ever colour up again. Even after more than a year, and despite experimenting with different lighting intensities while in quarantine.

If it is allelopathy, how long would it take to notice improvement?

Oh, and it's really weird. A few years ago, I accidentally broke a chunk off one of the acros, so I attached it to a frag plug. Anyways, it's colouration is much better, it's polyp extension is excellent, and it's skeletal growth is awesome, whereas the mother colony looks like trash and hasn't been growing.

Oh, and for some reason we can keep hammers just fine, but torches die after less than 8 months.

EDIT:
****. Yeah, it's probably the leathers. They're freaking massive. They must be gassing the poor stony corals. We'll get some carbon going in there.

[bertoni]

Recovery from allelopathy might take weeks, if you can cure the problem. Activated carbon might not be enough, depending on the level of chemical output in the tank.

For the frag that is doing very well, is it getting the same lighting as the mother colony?

The higher dissolved nutrient levels (phosphate and nitrate) might be causing a bit of browning, but that seems to vary a lot from tank to tank and species to species.

[teddscau]

We're going to rehome several of our soft corals (we're gonna pretend the mushrooms and zoas aren't a problem), so hopefully that'll help a bit as well. Darn the softies, I NEED my LPS corals. I guess the softies we do keep will have to be kept trimmed back. Man...I guess I'll have to trim back the palys since they're growing so fast. What a pain in the butt. Wonder if the coral stores we're going to on Wednesday will want any.

The frag does tend to receive better lighting and flow, although other frags we've made from the mother colony don't do nearly as well as that frag.

We're using the BRS carbon calculator, and we just put some carbon in (about a third of the amount we need so that the corals don't freak out). We'll slowly increase the amount of carbon over the next couple of months.

Oh, and thanks for the suggestions! We've been dealing with problems ever since we got the corals. We've (probably) solved the lighting problem, the phosphate problem (we actually had to add phosphates since we didn't have any), the bryopsis problem...and now the chemical warfare problem needs to be dealt with. I think that's everything. Should be fine after that.

[bertoni]

I'm not at all sure that the problem is allelopathy, but good luck!

[teddscau]

Eh, it's a place to start. Oh, I also neglected to mention that we have Caulerpa in our refugium and a little in our display. Just read that there's debate over whether or not it should be kept with stony corals. Guess we'll remove a bunch (we'll turn off the pump first), then drain the refugium to prevent the toxins from circulating in the tank after the macro's damaged.

We'll start pruning it back whenever we do a water change. I'll definitely be keeping some of it for lettuce nudibranchs (we're gonna order some soon), and the urchins like wearing it as well. Having Caulerpa in the tank for the urchins prevents them from carrying frags around and causing mischief.

[bertoni]

Okay, that sounds like a reasonable approach to me.