Poor Polyp Extension

[garyl]

I have an interesting problem in my tank. SPS (Acros and Montis) show very little polyp extension in my tank. If I put a hairy acro in my tank it will soon look like someone gave it a crewcut. The polyps are extended, but they are definitely not fully extended. The coral will continue to grow and shows no other signs of stress, it just won't fully extend the polyps. This is not just a single instance - it's been happening to me for years.

So, my question is - why?

Background:

Mixed reef - can toxins from the softies be affecting the SPS corals. Anybody out there with mixed reefs with similar experiences?

Lighting:

I used to have 400 watt Iwasaki 65k's, but just recently switched to 250 watt Giesseman 14.5's. No change in the problem.

All parameters that are easily measured are in tolerance. Since free phosphate is very hard to accurately measure, there is a chance that it might be problamatic; but I have no macro or hair algae in my tank, so I can't believe that can be the source.

That actually leads me to another question that may be an indicator - I have a very hard time growing any "healthy" algae in my tank or sump. I've introduced chaeto to my sump a few times, and it just languishes and slowly turns brown. It will live and grow, but just very slowly. I've always assumed I have little free iron in my system. Can lack of iron be a problem? Do hairys need iron supplementation?

This problem has persisted for years - it is not a sudden change. Anybody out there with a similar problem? Maybe we can compare notes.

Thanks in advance for any thoughts or advice,

Gary

[fanaglethebagle]

I find that my SPS have best extension with more nutrients than usual.

[garyl]

When you say "nutrients" what do you mean? Do you supplement with Amino Acids? I do have a good skimmer (made even better by a suggestion from Delta), but I've seen other tanks with "great" skimmers so I don't think I'm overskimming and causing the problem.

There are a lot of microfauna in the tank, so I've always believed there's lots of planktony-type stuff floating around and I don't often add any additives. I do infrequently use ESV Freeze-dried plankton, but I've never noticed any difference in extension.

Gary

[smcnally]

I'm no expert, but I was thinking just the opposite. I would think that lower nutrients would cause the polyps to extend more because they are stretching out to get more food all the time. I high nutrient tank would cause them to retract because they don't need as much food as often. I could be 100% wrong on this theory though :D

By nutrients, he means uneaten food, fish poo, etc.

[wrassefan]

Gary, flow is an issue also...some sps I get more polyp extension with more flow...others less. Depends on how strong the light was in the other reefer's tank that the frags come from....and yes, could be nutrients (alk levels, calcium levels, mag and phosphates).

[skyedolphan]

my first ?is what fish do you have ?
there are somefish out there that will make polyps retract ..
that was my problem for years and it took a long time to figure it out which was quite by accident but
many clown gobies and blennys will piss off SPS so they do not extend ..

also with a mixed I have heard it is mandatory to run carbon ( I have a complete mixed tank and rarely run the carbon LOL)

but maybe it will work for you ..

[garyl]

All good questions and suggestions.

I do run carbon - but not very much at one time...maybe it's not being used efficiantly? Hmm, how in the world would I know?

As far as fish go, I don't have an blennys, and the only clown goby I have managed to end up in my sump and has been happily living there for years.:rolleyes:

I've tried different flow and lighting - nothing seems to have any effect.

Recent Example: I bought a nice montipora from Dale (wow, what a tank!) a few months back - it had long dark-orange polyps in his tank. As soon as I introduced it to my tank, the polyps were clearly evident, but about one-half the extension. I've had it for two months now and it is growing and showing good color, but the polyps do not look anything like what they did at Dale's.

Gary

[jbundas]

That fact that you have no algae in the tank and trouble keeping cheato in the sump sounds like it could be a low nutrient issue. I could see the polyps reacting either way - retracting in a high nutrient environment because they don't need to work hard to get what they need, or retracting in a low nutrient environment because it's not worth expending the energy to stick them out and get nothing.

It might have to do with what is specifically available in the water as far a food for the sps corals. Maybe small dissolved organics can be directly absorbed by coral tissue but larger zooplankton type foods need capture by the poyls.

What do the polyps look like at night? Generally that's when the sps really wake up - no fish to bother them and more plankton in the ocean.

What kind of crap is your skimmer pulling out - a lot of foul smelling soup or a little bit of odorless sludge?

What colors are your sps? Lots of darker brown bases seem to indicate more of a high nutrient environment while lighter colors/less zoanthele are more typical of lower nutrients (zeovit systems for example).

I've been using Roti Feast for the last few weeks and the sps seem to respond very well with even more polyps and getting fuller color. That's something fairly cheap and easy to try out and see what happens.

[maxfischer]

Recent Example: I bought a nice montipora from Dale (wow, what a tank!) a few months back - it had long dark-orange polyps in his tank. As soon as I introduced it to my tank, the polyps were clearly evident, but about one-half the extension. I've had it for two months now and it is growing and showing good color, but the polyps do not look anything like what they did at Dale's.

Gary

Dale has the BEST polyp-extension i have EVER seen!! Wish we all new the trick:D

[fanaglethebagle]

I'm no expert, but I was thinking just the opposite. I would think that lower nutrients would cause the polyps to extend more because they are stretching out to get more food all the time. I high nutrient tank would cause them to retract because they don't need as much food as often. I could be 100% wrong on this theory though :D


I'm no expert either, but its just what happens in my overfed, skemmerless nano :)

[smcnally]

I'm no expert either, but its just what happens in my overfed, skemmerless nano :)
LOL, that's why I stated I wasn't an expert :D

[coldshutter]

Temp swings maybe?

[Carlo Miceli]

I experience the same things. GSP, and Gonipora and frogspawn have all died.. I have had a Torch Coral doing good for 1 mth. I started to think my Powder Blue Tang was eating the polyps and started the downhill swing..

[RichConley]

Nobody really knows what causes polyp extension.


Check the tank out at night, if the polyps are extended, chances are its a fish or light issue.

[Greg Hiller]

>my first ?is what fish do you have ?<

I was actually wondering more what type of fish load you have? I'm also thinking you might have an overly 'clean' tank.

Are you using any ozone?

[Carlo Miceli]

I do get more polyp extension at night. I did catch my PBT eating the items that died. I do have 3 hard coral frags that have shown good growth which makes me lead away from lighting.
Garyl do you have a PBT as well by any chance?

[garyl]

jbundas,

The polyps seem to be out more at night, however they still don't have that "hairy" look. Skimmer pulls out a lot of a stinky crud. I'll have to look at the bases for coloration. Maybe I'll give Roti Feast a try...

coldshutter - My temp usuallys fluctuates a few degrees during the day. However, you bring up a good point - I keep my tank on the high side 79-81 degrees. Could the temp be a factor? That's one of the few constants I've had over the years. If there's one thing I manage to do well, I can set a heater up.:rolleyes: I guess I need to take my small reefkeeping successes where I can.

Greg,

No, I don't use ozone. One of my examples is a beautiful hairy acro that I bought from you 4 or 5 years ago. In your frag tank it had polyps 1/4" long. Two hours later in my tank the polyps were 1/16" long. The coral grew for years, but the polyps never fully extended.

Carlo, No PBT.

Does anyone think temp might be an issue?

I keep coming back to the mixed tank as my probable culprit. As some of you may have noticed in other threads. My tank was, until very recently, filled with zoas and shrooms. I've gotten rid of most of that rock, but I still have a lot of softies.

Gary

[Aquadiva]

Dale has the BEST polyp-extension i have EVER seen!! Wish we all new the trick:D

anyone ever ask Dale?? Seems to me, that folks that have that great polyp extension seem to know exactly what is wrong when they don't see it. ;)

The rest of us are just left to wonder...:(

[Aquaman_68]

Lighting. yes!! Flow. Yes yes!!! What type of food do you feed your tank? Too much no good too little still no good. The fact that you can't grow cheato doesn't mean bunk in my book. I have sick polyp extension in my tank & I fight to grow cheato. (which usually means your water is low in iron & nutients) Some corals will not fully extend their polyps out until the lights go off. Those are usually because it is an effect of the lights(some different types of acros in my tank are like that. Montis & millis are always wide open during the day) Andy made a good point as well...I recently went a little sick with flow in my tank. (aprox 9040 GPH when all cylinders are firing at full flow) You know.....Some of my acros in the tank are digging it big time. A few of the lower flow species are a little pissed but they are adjusting fine as the weeks go by!!
If all the paramenters are in check.(btw...What is your SPG?) I would also consider if theres a chemical thing going on. Either by means of water replenishing or chemical warfare. What type of TDS readings are you getting out of your product water? Does your water supply use chloramine? Do you use an adequete means of removing the free ammonia that is left behind after the carbon removes the chlorine? (which is a part of chloramine...IE Chloramine= chlorine & free Ammonia) Ammonia levels in a tank (by means of decomposition of food or fish waste are toxic & are easly removed thru water changes or the bio cycle, but free ammonia is nasty & very tough to remove. (Almost impossible) your regular ro/di units out there when they have new filters will remove a good portion of it (below the detectable levels with conventional test kits...ppm ranges but not in the ppb ranges) but only for a short time. These filters will be exausted very quickly. The trick to removing free ammonia is relying on your di resin to remove it & also by using catalytic carbon pre ro. But to get all the free ammonia out post ro the ph has to be below 7.0 or around that range. Most tap water has a ph up in the mid 8's & some city water supplies can peak into the 9's. That is too high to succesfully remove the levels down to the ppb range or even down to one ppm...
Using mixed resin beds in conjunction with straight resin beds is the best way. Use a mixed resin bed with a low ph in the first chamber that will actually lower the ph into the 7 range & then second chamber will remove the free ammonia down into the ppb levels......
Hope I'm not making your head spin...But...this is the advanced forum & now I can let it rip!!!;)

Hey...one last thing....For some reason (after doing quite a bit of reading & researching) I've found that it seems to be evident that people using well water benefit from the presence of maganese. (which seems to be rich in well water, as well as all those heavy metals!!!) Even after filtration thru osmosis some traces are left behind & are benificial to a reef tank. (sometimes I wish I wasn't on city water for this very reason & the fact that it is all over the boards with seasons & garbage they put into it!!!)
I guess that subject is for another thread as well as alot of stuff I've mentioned!!! Sorry if it's too much to read!!!
B

[garyl]

B,

You raise a number of good points - although I have to point out that I would be lying if I said I understood everything...:rolleyes:

My salinity is pretty constant at about 1.025. I use a Kent marine RO/DI Hi-S unit with a TDS output reading of "0". I change the filters about every 6 months or whenever I see the pressure go down on my unit. I am on city water. I don't know about the chloromine.

I run carbon constantly. However, I did run it every other week for a while (as mentioned in other threads) to see if that made any difference.

I just changed my lighting a month ago from 400w Iwasaki 65ks to 250w Giesseman 14ks. I also have 4 48" T5 actinics over the tank.

The only real constant in my tank has been the mixed softie/LPS/SPS.

Just to make sure everyone understands. I'm not saying the polyps never come out in my tank. I'm saying if I was to buy a "hairy" SPS, you would never know it once it enters my tank. It almost makes me question if "hairy" is a type or a reaction.

Everyone, thanks for the input and food for thought.

Gary

[Greg Hiller]

Just in the FWIW category, your tank might actually be more like the natural environment. Anyone that's been diving on a Pacific reef can tell you that during the day polyps are generally not extended much on any Acros. That may be due to fear of predation, or due to higher currents in the natural ocean. Or it may be that in really nutrient rich systems (like most of our) the corals extend their polyps to more effectively absorb the nutrients.

If you are getting good growth, I wouldn't sweat the polyps extension thing, unless you really want them extended. You may be right that it's a chemical warfare thing....more agressive use of carbon, more water changes, or maybe even ozone might help?

[scavdog]

I agree with Greg. Here is an excerpt from Advanced Aquarist from 2002 that you may find interesting:

It is a common belief that corals expand at night in order to feed on planktonic prey. However, what is forgotten is that water flow and light levels also play an important role. This paper describes a study conducted in the Red Sea on Favia favus, a massive coral who's polyps open soon after sunset and retract just after dawn. Their results indicate that three factors: flow rate (low= 5 cm/s, medium = 10 cm/s, high = 15 cm/s), light level (low = 40 umol/m/s2, medium = 80 umol/m/s2, high = 120 umol/m/s2) and prey presence (Artemia nauplii), determine the degree of polyp extension at night, but flow rate and light are the main triggers. Tentacle expansion was greatest when water flow was high, light levels were low and prey was present. When no prey was present extension was only 75%. In still water the corals would not extend their tentacles even if light levels and prey density were varied. When light levels are too high (above the light compensation point of 107 +/-24 umol/m/s2) the coral would not expand no matter what the flow was or if prey was present. If no prey was present, and the flow was medium or high, and light was below the light compensation point, then the corals still expanded, indicating that the coral's response to the presence of prey was secondary to water flow and light level. The authors also concluded that since the zooxanthellae density in this species is low, extending the tentacles during the day was probably metabolically more expensive than keeping them closed. They felt that their results may not be applicable to corals with high densities of zooxanthellae and that these corals would be more likely to benefit from expanding during the daytime.

For the aquarist the lesson here is that flow rates need also be taken into consideration when it comes to determining feeding in corals at night. Too low a flow may result in some corals not expanding and hence, not being able to feed. This lack of polyp tentacle extension could be mistakenly interpreted as sign that the coral does not need to or want to feed.

[smcnally]

In Calfos "C The Journal", he also explaines that "Great Polyp Extention" can also be a sign of a coral starving.

[reefinghabit]

i would check alkalinity if thats no issue. i think maybe tank is to clean as greg stated. corals thrive on nutrients ie phosphate nitrate. even dissolved detritus. fish may be picking on the polyps. you dont however want to encourage phosphate build up. maybe try feeding a good plankton food. strong flow is great for acros especially the long polyp ones.

[KenG]

I have had a similar experience. We have a mixed reef and saw poor polyp extension on SPS. Pieces with large polyp extension when purchased shrunk to no extension in my tank. Things did not die, but did not grow fast either.

I added carbon to absorb toxins from the softies. Not real difference in polyp extension, but the water sure looked clearer.

Then two things changed at the same time. I switched from my poor 10K XM bulbs to new 10K AB bulbs which showed markedly whiter light. I also finished my first gallon of Randy's two part and dosed Mg. So I upgraded lights and dosed Mg to a level of ~1600. Since then my SPS polyps have been fully extended and growth is markedly faster.

That is just my experience. I have always had good chaeto growth and have never had a zero nitrate reading (always 10-20) or a TDS reading below 5.

[delahunt]

i have similar problems with polyp extension in my display tank, but in my frag tank everything flowers.. cant quite figure it out either

[besl]

KenG - interesting commnet on Mg - I thought Mg was suppose to be between 1200 - 1300 - are there ill effects by raising to 1600?

Why I ask... I've read alot on PE looking including what I thought was an excellent thread on RC - Randy H made a comment that he uses IO salt which he has measured the Mg to be around 800. The thread was tied to the topic of PE and the claim was made as to how important Mg was. As I use IO salt, I convinced myself that I had an Mg problem so I immediately ordered 2 different Mg test kits and 2 bottles of Mg - after all, Randy said that IO was only 800. My test kits came and guess what - one measured 1250 and the other measured 1320. Oh well, anyone want to by some Mg or test kits? Meanwhile I join your quest to find why I have poor PE on many sps while very good PE on others.

[jebar777]

FLOW


FLOW IS ALWAYS AN ISSUE WITH POLYP EXTENSION





good luck

[garyl]

By flow, I'm assuming that you mean strong flow. I do have pretty strong flow (of the linear powerhead sort). I haven't seen any difference in my tank's polyp extension when I change corals from good flow to really strong flow. That being said, there is the possibility that I have the wrong kind of flow. Even though I have the powerheads on a wavemaker, it's still linear flow.

I'm just happy to see from the thread, that I'm not the only one with this problem. If possible, I'd like to hear a little bit more from KenG about keeping his Mg at 1600.

Thanks for all the suggestions, you've given me a lot of food for thought.

Gary