LPS RTN at dusk / dawn

Fragzilla · Jul 30, 2017

Hello,

I'm looking for some advice if you don't mind please.

I had this ussue last year where a lot of corals RTN'd over night while the rest were mad with sweeper tentacles out for several months after, it was horrible

I'm seeing the first signs of this happening again.

I saw it first when I switched my refugium light over to a different unit. Now during the "dusk and dawn DT light and sump light overlap" (2hr) I'm seeing signs of distress, but not RTN damage like I saw a couple of days ago when the light was changed.
When I switched the sump light 2 days ago, 2 of my acans colonies and my encrusting funghia melted away at the edges overnight.

It happened this time last year. Is it possible this could be a seasonal thing? I.E pollen/carbon contaminants, atmospheric CO2 rise, airborne pesticides?
And the fuge exacerbating the contamination in some way?

I thought last year it was due to hydrogen sulphide in the sand bed being released with PH fluctuations caused by removing a lot of chaeto and stopping rowa reactor, I did end up removing the sand bed and installed a new 1" KZ gravel sand bed which to be honest i had given minimal attention too (other than adding some nas snails), could sulphide compounds build up in just 1 year?

I'm kind of on the edge of my seat right now, not sure if I should just drain down and remove the sand bed or wait it out and don't touch the fuge. I've taken my skimmer cup off to attempt to mitigate any more reactions if it is due to the pollen / carbon low nutrient thing.

SG 1.025
KH - 7.8
Cal - 390
MAG - 1230
NO3 - over 4ppm (Red Sea test doesn't go higher)
PO4 - low, 0-0.04ppm

Tanks pro dominantly LPS and zoas/palys now, with a couple of Montipora species.

Fuge has chaeto in, although it's not looking it's best, probably because I'm a bit over zealous with the reactor due to my fears of iron and Hydrogen Sulphide being at play.

No temperature fluctuations (got air con now)

Not good

I've only just got the tank back on track.

Any comments/suggestions are greatly appreciated.

TheLadyCrash · Jul 30, 2017

It's very possible time of year could be involved especially around pH fluctuations which could cause imbalances with your other params. For example, if you normally have your windows open but now have the house closed up because of the summer heat, that change could cause more drops in overnight pH (or pH flux in general).

I wish I had more answers for you, but unfortunately I can only say that season does seem to impact this hobby in many ways.

Fragzilla · Jul 31, 2017

Is there a chance my PH could be going too high?

It seems it happens when the sump light comes on in the evening during that overlap period.

I've always read that PH is highest at the end of the day.

I tested PH yesterday, probably not the best test kit, and the colours were indicating 8.2-8.4

There seems to be a direct correlation with either increasing fuge lighting or reducing GFO use, im guess talking GFO out will raise PH as will increasing fuge lighting.

At the moment the damage on the corals seems to be at the shaded sides

Randy Holmes-Farley · Aug 1, 2017

Fragzilla said:
Is there a chance my PH could be going too high?

Not unless you are dosing large amounts of limewtaer/kalkwasser.

That is the only scenario where pH gets too high (that is, well above pH 8.5).

Fragzilla · Aug 1, 2017

Ok I've been doing a few tests.

PH doesn't seem to be swinging too much although I tested alk in the evening before fuge light came on and it was 8, an hour after fuge came on it was 7.6-7.8.

PH test is indicating it's always over PH8, usually 8-8.4

I'm theorising that I'm suffering from low carbon dioxide. It's high summer here in the U.K. So I guess oxygen levels must be at a peak plus lots of vegetation where I am so that I guess is sucking all the co2 out the atmosphere.

When my sump light comes on in the evening 2 hours before my display lights run down I believe the chaeto is taking up bicarb in leu of carbolic acid.

Is this theory probably Randy? It's the only thing I can think that could be going on to upset all my corals at that time of the day.

Once DT lights go off the corals settle down. So it's not just the fuge light causing this, it only seems to happen when both sets of lights are on.

miyags · Aug 1, 2017

I'd raise your Alk,Cal and Mag. Also look in the tank about 4 hours after lights out,to see if something is eating them. Astrea star fish or arthropods

Randy Holmes-Farley · Aug 1, 2017

Fragzilla said:
Ok I've been doing a few tests.

PH doesn't seem to be swinging too much although I tested alk in the evening before fuge light came on and it was 8, an hour after fuge came on it was 7.6-7.8.

PH test is indicating it's always over PH8, usually 8-8.4

I'm theorising that I'm suffering from low carbon dioxide. It's high summer here in the U.K. So I guess oxygen levels must be at a peak plus lots of vegetation where I am so that I guess is sucking all the co2 out the atmosphere.

When my sump light comes on in the evening 2 hours before my display lights run down I believe the chaeto is taking up bicarb in leu of carbolic acid.

Is this theory probably Randy? It's the only thing I can think that could be going on to upset all my corals at that time of the day.

Once DT lights go off the corals settle down. So it's not just the fuge light causing this, it only seems to happen when both sets of lights are on.

Low CO2 is not an issue for corals unless it means the pH is excessively high. Low carbon dioxide gives high pH. While at pH 8.4 there is no concern with low CO2.

Fragzilla · Aug 1, 2017

Randy Holmes-Farley said:
Low CO2 is not an issue for corals unless it means the pH is excessively high. Low carbon dioxide gives high pH. While at pH 8.4 there is no concern with low CO2.

Unless my PH tester is out and it's actually higher than I'm reading, it isn't easy differentiating between the colours.

Could you suggest what might be happening to my corals then please?

I'm not clever enough to know outright, just guess. Something's going on and if I make a change to the fuge or reactor bad stuff starts happening, unless it's as I first thought and it's sulphurous compounds

Randy Holmes-Farley · Aug 1, 2017

Fragzilla said:
Unless my PH tester is out and it's actually higher than I'm reading, it isn't easy differentiating between the colours.

Could you suggest what might be happening to my corals then please?

I'm not clever enough to know outright, just guess. Something's going on and if I make a change to the fuge or reactor bad stuff starts happening, unless it's as I first thought and it's sulphurous compounds

High pH is not an issue.

That said, I do not know what the problem is. There's no apparent issue with the parameters you post, and the problem may be other than chemical. Do you do regular water changes?

It may be a biological problem (pathogenic bacteria or viruses, something picking on them, etc.).

Fragzilla · Aug 1, 2017

I do about 10% each month as I'm dosing the reeflowers easy balling.

It's definitely RTN'd, I watched it happen first over a evening. Was fine and then roughly an hour after lights started coming down the acan shrunk down and then the flesh started coming away, the skeleton underneath is bright white, some polyps are kinda dangling off the side of the colony where they've receeded and are hanging from a thread.