Undetectable issues with my tank (zoanthids dying, etc.) - Ideas?

[kyley]

Hi All,
I'm in need of some assistance from the experts here as I'm having issues with some corals lately - primarily the easiest of corals - zoanthids. I'm providing a lot of detail so you can help troubleshoot, so I apologize if this gets long. I've been running a Red Sea Max 250 (65 gallon) since December (nearly 8 months now). I'm a careful reefer - I've stocked my tank slowly, I iodine dip new corals, I quarantine new fish, I research all my purchases, etc. I've done all I can do to maintain the best possible water quality (most of this was setup months ago) - here's my setup:

• I upgraded the stock skimmer to a Euro-Reef / Nano-Reef 2-pump skimmer
• I added a basket with Chaeto to the DT for nutrient export (plan on a fuge eventually).
• If anything, I think I underfeed rather than overfeed (always been careful with that). Plus, I rinse all my frozen food in RO/DI before adding to the tank.
• I replaced the media shelf bags with a TLF media reactor and use Bulk Reef Supply ROX carbon, High Capacity GFO, and SeaChem Purigen in the reactor (also a bit of SeaChem SeaGel [carbon/phosguard mix] too).
• Added Vortech MP20, Koralia 1, and Koralia 2 for good flow throughout the tank
• I do regular 10-20% water changes every week.
• I run a chiller to maintain a stable temperature (80 degrees).
• About 73 pounds of rock (55 was live rock); 69 pounds of sand (29 was live sand) is in the tank
• I have a dosing pump that keeps Alk, Ca, and pH stable and Mg is dosed with my ATO water; pH is monitored with a pH probe.
• I have an ATO to keep salinity constant
• I use a 5-stage RO/DI unit that reports 0 TDS.

Current tank stats:

• Alk is usually 8.6-9.3; Ca is 420-460; Mg is 1280-1320; Salinity is 1.026
• pH range is about 8.22 (night) - 8.38 (day) typically on the highest and lowest ranges.
• ATO keeps salinity stable at 1.026.
• Since cycling, I've never had Nitrates detectable above 2 (with Salifert test kit - but almost always 0) or 0 (with API test kit). Nitrites, Ammonia, and Phosphates (API test) have never been detectable either. I've tested my freshly mixed SW and have 0 on all these there too.
• Inhabitants include 5 small fish, about 20+ snails, 6 hermits, 1 emerald crab, 2 shrimp, 1 crocea clam, and a lot of corals.
• No algae issues - tiny amounts of hair algae in a couple places, but nothing more and it's not growing. Cyano has been a problem though.
• I've never lost a fish in my DT, and other than zoanthids and a blue clove polyp frag that I had for awhile - and a couple frags that didn't last at all - I haven't lost any other corals. I've lost some snails (normal right?) and an urchin, but no crabs or other motile inverts.

My problems:

• Mainly zoanthids and palys. They all seem to be unhealthy (many unopened, apparently tissue has melted as there are now isolated polyps, etc.). Many months ago I had zoa nudis - got rid of them with Iodine dips. I had zoa pox - got rid of that with Furan-2 dips. About a month ago I started having brown gunk (apparently a brown jelly type disease after researching) on them - it appears I successfully got rid of that too with hydrogen peroxide and freshwater dips. I don't see any zoa pox, nudis, or brown jelly now, but the zoas are clearly indicating something's wrong. For whatever reason, this easy coral has been very hard to keep! Does it sound like some kind of disease? Any ideas what I can do? I have about 8-10 colonies and pretty much all of them are not looking well.
• My finger leather (specifically, green palau nephthea I believe) has been closed up for the past 3-4 days.
• I've had a substantial case of cyano that I siphoned out, treated with Microbe-lift Special Blend (simply beneficial bacteria), etc., and essentially got rid of for a couple weeks. It's come back recently (not as bad as before though) - and I suspect the zoanthids dying may be part of the reason. At any rate, I've seen enough people with cyano, yet great water quality / test results, to become convinced that cyano is a stage some tanks go through (like diatoms) regardless of nitrate / phosphate levels.
• A single green clove polyp (not GSP) is closed much of the time, though it does have a baby or two growing.
• My Duncan colony has been closed much of the past couple days.
• All SPS and LPS corals are looking fine, extending, and growing (the only exception being my Duncan which closed up a bit the past couple days). My mushrooms and ricordeas are doing great too. Toadstool leather has closed a bit, but not as bad as the finger leather.

Any ideas on what's going on / what I can do? I'm pulling my hair out because I'm doing all I can to keep great water quality, apparently am, but am having these issues (mainly the zoanthids)... Here's a picture of the zoanthids (you'll see some cyano, but I had cyano on the zoas previously and they never closed - so don't think that has anything to do with it):

One thing I do plan to try (when my order comes in) is Coral RX on the zoas. It just seems maybe there's another problem that I'm not seeing... Thanks in advance,
--Kyle

 

[Floowid]

Sounds very mysterious. Did you buy the tank used? The reason I ask is because bad lights can do all the things you are describing. If the tank is new and only 8 months old, then the lights can't be that bad yet, but if they were used before you got it...

You might also try watching the tank in the middle of the night with some sort of red flashlight, to see if maybe a gorilla crab is in there wreaking havoc on your inhabitants.

 

[jasonrp104]

I'm wondering if your tank is too clean. If cyano is eating up what little crud you have so your softies are starving.

 

[kyley]

Hmm... Interesting thoughts (too clean, lights). Not sure what I'd do there other than overfeed! Anyone had such a "too clean" issue before?

The tank was purchased new, so the lights are 8 months old. I have been planning on replacing the lights soon and wondering if that could be a cause. Although since my SPS seem to be doing fine - do you think that lighting could really be an issue?

I'm a night owl so sometimes near the tank as late as 2 AM - don't see anything. I'm pretty sure I got all the bad hitchikers out - except for a giant flatworm that I know has eaten at least a couple snails (heh, hopefully it died and caused the cyano, LOL).

I should also note - most of these zoas have flourished (grown all over the place) and have been in my tank since shortly after completing the cycle.

Thanks - keep the ideas coming!
--Kyle

 

[chrishet]

I had some very nice zoos that closed up and appeared to be dying. It was recommended that I not do so many water changes. I switched from 15% water changes weekly to 10% bi-weekly...I was also not running a skimmer so started that up again...it didn't take long before my zoos started to flourish again...could have been a case of too clean but don't know for sure...maybe chemical warfare....my 2 cents....

 

[mike_cmu04]

Maybe i missed it but what kind of lights do you have?

 

[kyley]

Sorry I didn't include the lighting - 6 T5 VHO lights (3 are actinic) - providing over 4 watts per gallon I believe. That's one of the few things that's "stock" in my tank.

Chemical warfare couldn't really be the issue - they aren't near any aggressive corals (and they're in many spots in the tank - but all are exhibiting these issues). Take care,
--Kyle

 

[ta_billy]

Sorry to say that I have seen this in my own tanks...looks like a bacterial outbreak or something or other. I never figured it out. Might be small parasites or other, but it seems to spefically target zoas. I had a few morphs that seemed to ignore the outbreak and had others that totally succumed to the "thing". I have read that zoas are prne to bacterial outbreaks so that my guess.

 

[chrishet]

Chemical warfare couldn't really be the issue - they aren't near any aggressive corals (and they're in many spots in the tank - but all are exhibiting these issues).

Just an observation, but corals do not necessarily need to be close to each other to react, they are all sharing a relatively small space compared to their natural environment. However if you are running carbon then you are probably ok...

My suggestion is to not do another water change for a few weeks and see what happens...I am no expert but it seems to me that water that is 'too' clean would be problematic. Corals thrive in low nutrient waters, not nutrient free water. If we eliminate all phosphates, trace elements, and all other nutrients, then what is left for our corals? at least those that rely on some nutrients or symbiotic relationships to survive...

Another thought, I recently had a prized acan recede badly. The only thing that changed in my system was some GFO in a media bag. I removed it and within 24 hours it opened back up, fully...I guess I added too much GFO at once, next time I will start off small...GFO has been known to cause coral to retract. Good luck and I will follow this one for sure...

 

[kyley]

Hi All,
Thanks for the help. I can't say what "fixed" the issue, but everything is back to normal in my tank (about all I did was dip the zoanthids in Coral RX - which may or may not have had anything to do with the recovery). I lost a few polyps of zoas from a few colonies, but everything has come back strong now - no closed polyps anywhere. My finger leather fully opened up again, same with the duncan colony and clove polyps. They've all been like that for weeks now, so everything seems very healthy! I guess I do have a couple big button polyps that have never seemed fully recovered, but they were a freebie frag anyway (could just be that they don't get enough light). Still battling some cyano too (that's been a nightmare of its own). Take care,
--Kyle