Can't explain slow coral die-off.....opinions wanted

[pinstripe]

Hey all, been forever since i put up a post, but I am in need of help and I know that the knowledge on this forum is great....been using and contributing for years.
I'll try to be brief:
70 gallon tank, up and running for 4 years
150w, 14k metal halide w/ 2x96w PC actinics
Reef Octopus skimmer
Fluval 405 canister
All levels within ideal range, with few exceptions, which i will get into
I had over a dozen different corals of all types thriving for years, then about 6 months ago, my enormous bubble coral's tissue started to recede, all of my zoas died, mushrooms became smaller and fewer, green star polyps died off. On the flip side, my frogspawn is HUGE, my green tip anemone is thriving as a host for mated clowns I've had for 5 years. The only thing left outside of those are a few red mushrooms and a bubble that is clinging to life.
No new fish added in years. As I said before, all levels at ideal marks, except for magnesium, which is a little low (1200), and kH, which is a little low (8-9). I use R/O water for replenishment, and do regular water and filter changes.
I had a theory that there was chemical warfare between the corals, but if that's the case, I would think the anemone would suffer. Also, the coralline algae on my rocks is decreasing, which is a big mystery to me because i used to be able to add base rock to my tank and it would be covered in purple in a month.
Any thoughts or suggestions would be appreciated.
Thanks in advance everyone!

 

[ibew41]

what are your exact numbers of cal alk and ph what test kit are you using pics would also help

 

[pinstripe]

pH is usually 8 in the morning, 8.2 in the evening
Calcium is 460 ppm
dKh is 8.4
phosphates less than 0.03 (always been at this level)
temp 78 in the morning, 81 in the evening
salinity 1.022 with refractometer
magnesium 1200 as of this morning
Calcium, Alk, and Phosphates I use Red Sea Professional Series test kits - used to use Salifert but had dificulty reading.
Magnesium I still use Salifert
(I also have Salifert tests for Iodine and Silica)

 

[bang guy]

What other water flow do you have for the tank?
Have you rtested your RO water recently?
Whan is the last time you ran some GAC in the canister?

 

[pinstripe]

I run 4 hydor power heads each at 400 gph, plus the turnover from the canister and the skimmer.
R/O system is brand new, spectrapure 3 chamber 90 g/day
Canister has 4 chambers,
First chamber - coarse pre-filter ceramics
Second chamber - smaller ceramics
Third - polishing pads
Fourth - activated carbon by Kent
this canister also houses 4 sponge filters

 

[ibew41]

salinity is a little low how often do you replace carbon in canister and really clean filters in canister

 

[pinstripe]

aye-aye on the salinity.....i've always kept it around 1.023.....should I go higher?
the carbon in the canister should be replaced at most every 10 days, but admittedly, I don't do it that often, probably once every 3 weeks.
I replace the sponges in the canister every 60 days, and the polishing pads every 30. The ceramics I only rinse with saltwater when i do the sponge changes....just to knock off all of the built up detrius, but I don't scrub them clean for obvious reasons.
What do you guys think about temp????? The die-off seems to coincide with summer....but I have the A/C on to keep the house at 76, so the tank really never gets above 81. However, in the winter, it usually sticks around 76 in the tank.
Thoughts???

 

[bang guy]

Has the decline started since you installed the new RO system? What does the TDS meter read on the output?
I'll assume bulbs on the lighting are changed regularly.
Do you have a deep sand bed?
I don't believe the temp is high at all. I would typically keep the corals you listed at 83 - 85F.
The salinity isn't really low enough to do harm in my opinion.
My recomendation on GAC is to run fresh GAC once a month for only two days. No doing it that way isn't going to really cause any harm though.

 

[pinstripe]

I bought the new RO in response to the decline, so I don't think that could be the cause. The only meter on my RO is PSI, so I don't know what the TDS would be.
Bulbs are changed every 9 months, current ones are new as of 3/22. That is interesting.........but they were exact replacements for what I had before the change, brand and all. I am considering switching to LEDs this winter, but that is a different discussion.
Sand bed is roughly 2 inches give or take. Another point to note, I have a difficult time keeping nassarius snails because my blue hermits attack them. Also, i like to keep mexican turbos because of their cleaning capacity, but they have been tough to keep lately, I've probably lost 4 in the last 3 months, not to attack, just death. I know this is a sign something is wrong, but I don't know what.

 

[snakeblitz33]

How often do you do water changes? What salt are you mixing? Have you changed salts recently? From what to what?

 

[snakeblitz33]

Have you recently calibrated your refractometer to make sure that is your correct salinity?

 

[pinstripe]

I use IO Reef Crystals and the refractometer, i just checked, zeros out with R/O water. I also have a hydrometer as a backup that corrects for temperature in relation to specific gravity, which is really what I am talking about (sorry for using SG and salinity interchangeably before), and it checks out.
I do very few water changes, maybe 5 gallons every other week or so, but I have always done it that way. In other words, I know it isn't ideal, but it is no change compared to anything I have done before. Same food, same light cycle.....I wonder if there is something micro-organic that I have inadvertently introduced?

 

[snakeblitz33]

Stirred up your sand bed at all?

 

[pinstripe]

Lately, yes, last week, which explains a temporary jump in NitrATES....I was doing a massive cleaning, tank looked like hell and had to get some detritus out. I really can't say if I did that to begin with though.
The only thing that I can remember and have documented that sort of correlates to the problem is that my anemone split in two a while back, and one of the halves started walking all over the tank. Finally, it put itself deep, in the back......not an ideal place by any means.....and it definitely died. Could toxins kicked this off? But if so, why do I have continual problems and no bounce back?
Even if this is the origin, there has to be a problem currently. Thank you all for your responses, and please keep the ideas coming. I want to get my tank back to it's glory days!

 

[flower]

Quote:
Originally Posted by Pinstripe http:///t/388494/cant-explain-slow-coral-die-off-opinions-wanted#post_3426509
Lately, yes, last week, which explains a temporary jump in NitrATES....I was doing a massive cleaning, tank looked like hell and had to get some detritus out. I really can't say if I did that to begin with though.
The only thing that I can remember and have documented that sort of correlates to the problem is that my anemone split in two a while back, and one of the halves started walking all over the tank. Finally, it put itself deep, in the back......not an ideal place by any means.....and it definitely died. Could toxins kicked this off? But if so, why do I have continual problems and no bounce back?
Even if this is the origin, there has to be a problem currently. Thank you all for your responses, and please keep the ideas coming. I want to get my tank back to it's glory days!
The stirred sandbed is most likely the cause. There could be more going on than just a jump in nitrates, toxins could have been released if the sand has not been moved in a while. I would think the carbon would have taken care of it and any chemical warfare between corals or a dead anemone too...How old are your test kits?

 

[pinstripe]

Just to be clear, I agree that the stirred sand bed could be the reason for the recent increase in 'TRATES...and I concur, that toxins may be in the water, and I am currently doing 5 gallon water changes every few days. Flower, your assessment is dead on. All of my RedSea Pro's are brand new....Saliferts are older, but still in date. Trates test is probably less than a year old.
The stirred sand bed isn't the cause of my original problem, because I didn't stir it way back when the problem started. I guess what I'm getting at is that I think that I have one parameter way out of whack.....maybe something I'm not testing for? What's crazy is that when I started this hobby 6 years ago, I jumped right in (foolishly) and had success from the get-go (luckily).....Over the years I have learned more about all aspects, and now that I have a greater knowledge, I can't figure this out....go figure!
Keep the posts coming guys, I welcome the advice.
As an update, I am currently doing the water changes as described to increase SG (slightly, slowly), increase kH, and decrease nitrates.

 

[snakeblitz33]

Have you calibrated that refractometer with a 35ppm solution? Sometimes salinity drops too low or goes too high even with the supposedly calibrated instruments we use.
Check your RO waters Tds, just to be sure.
When did you run carbon or GFO? Have you ever used an aluminum based phosphate remover?

 

[pinstripe]

PhosBan a long time ago, but that is iron based i think.

 

[pinstripe]

UPDATE
So It's been a week, and I tested all my levels again, and my nitrATEs are still up (40ppm). As I think of it, I don't have it written in my tank log if I tested when this started. I know I did along the way, but I know it was very old testing material. So now I am going to go on the assumption that my TRATES have been the problem all along, and they have gone undetected. My tank is exibiting all of the symptoms.....algae problems, coralline recession, invert deaths and coral die-off.
SO....I am continuing my water changes, and removing the biomedia from the canister filter. I refuse to do this chemically as it is almost never the answer. And, it should go without saying, I am gonna test more often WITH unexpired tests!
I'll try to keep this thread updated, although it may be a long haul!