Acros dying and no idea why....

[Overfloater]

Hi,

I am having a problem with several of my acros dying recently. Basically the entire tank is on it's way down at this point. Flesh is peeling quickly. Some have bleached. RTN/STN is rampant.
Most acros have not had any polyp extension at all in several months. Even at night. No fish nipping and I have inspected for pests and none were noted. Several corals I have added had great polyp extension for about 2 weeks after which it disappeared never to return. This process occurred several times .

Cali tort has been in for a little over a year and had grown pretty well. This one always had polyp extension but a week ago it disappeared and a few days later flesh started peeling.
ORA Green Planet was added in March and was always hairy and grew well up until a week ago and is now exhibiting the same problems as the cali tort.
ORA Red Planet was added a month after the green planet. Initially had good polyp ext but after two weeks it was gone. No growth at all in 5 months and it slowly STN from the base.

The only change I made recently was to allow the skimmer to drain back into the sump in an attempt to fix chronic low nutrients and dosed Red Sea AB+ a few times. That was about a week ago and all these problems started after that. Also, I reduced my 2 part dosing after finding the Alk had climbed from 8 to 12.5 back at the end of July for an unknown reason. So in 2 months it has dropped to 8.4. Shooting for 7 due to low nutrients.

It's a Red Sea Reefer 350 (approx 75G) with two Gen 4 XR30 and has been up for 22 months.

Alk 8.4
Ca 420
Mg 1540 (haven't dosed this in several months)
PO4 7ppb (Hanna ULR)
Nitrates ?? (historically almost undetectable)
Salinity 1.026
Temp 78F
XR30 are 16" AWL and 80% AB+ for 8 hours.
MP40 x2 for flow
Barebottom
RO/DI is 0 TDS

Only nutrient control is the skimmer and monthly 15%WC with IO.

Fish List:

Yellow Tang
Squareback Anthias
Bangai Cardinal
Six Line Wrasse
2 Blue Chromis

Tested stray voltage and its 46V
The fact that I don't get polyp extension even at night except on that cali tort/GP prior to the last week has always concerned me. Clearly something is off but I don't know what it is. I have a squamosa clam that has been in the tank for a year and it has grown significantly and is always fluffy. I thought clams were difficult but honestly, it has been by far the best growing organism in the tank.

Sorry for the long read. Any help would be appreciated.

 

[Reefer40b]

" Tested stray voltage and its 46V "
First off this maybe the issue.... did you find the culprit? If not start unplugging things one by one until you find it

 

[Overfloater]

Reefer,

Thanks for the help. Yes I have tried to isolate the problem. 20v comes from my return pump and 8-10v from each heater. This accounts for about 40v.

It's odd because if I unplug those items I am left with about 13V. This is with nothing running except lights and MP40s so there should not be any voltage in the tank. If I power off the power strip and plug the pump and heaters in, the voltage drops to less than 1V. This leads me to believe those items are acting as a grounding probe.

 

[kenchilada]

How are you measuring the stray voltage. Maybe I’m not following your description but something sounds odd.

I was thinking your issue was nutrient/stability related.

 

[xxkenny90xx]

Any reason your not getting rid of these items that are leaking voltage???

 

[smacbride]

Shouldn’t your “stray voltage” be 0?

 

[xxkenny90xx]

Shouldn’t your “stray voltage” be 0?

A small amount of voltage is considered "normal". 46v is not

 

[EW_Fish]

Have you tested the voltage before?

 

[Overfloater]

Have you tested the voltage before?

No, I have not. I checked my other tanks and one has 24V and the other 34V. Both tanks have nothing but lights, heater, and return pump.

From what I am reading it seems some stray voltage is to be expected varying based on how much equipment is installed.

This tank is not on a GFCI so I will be taking care of that shortly. In the mean time, I have installed a grounding probe and stray voltage now reads 0.

At this point, I have lost most of the acros in my tank. A few seem unaffected, as are my squamosa clam, jawbreaker mushrooms, and goniopora.

I'm not convinced the voltage was the issue for the rapid decline (I guess you would call it a crash at this point), however it may be the reason I have had such poor poly extension over the last several months.

I think it was caused by a rapid increase in nutrients due to dumping my skimmer cup into sump (cup was 1/2 full) and thereafter allowing the skimmer to drain into sump, even though I have chronically low nutrients and testing after the skimmer dump only showed 7ppb PO4.

 

[xxkenny90xx]

No, I have not. I checked my other tanks and one has 24V and the other 34V. Both tanks have nothing but lights, heater, and return pump.

From what I am reading it seems some stray voltage is to be expected varying based on how much equipment is installed.

This tank is not on a GFCI so I will be taking care of that shortly. In the mean time, I have installed a grounding probe and stray voltage now reads 0.

At this point, I have lost most of the acros in my tank. A few seem unaffected, as are my squamosa clam, jawbreaker mushrooms, and goniopora.

I'm not convinced the voltage was the issue for the rapid decline (I guess you would call it a crash at this point), however it may be the reason I have had such poor poly extension over the last several months.

I think it was caused by a rapid increase in nutrients due to dumping my skimmer cup into sump (cup was 1/2 full) and thereafter allowing the skimmer to drain into sump, even though I have chronically low nutrients and testing after the skimmer dump only showed 7ppb PO4.

A grounding probe without gfci is not a good idea.... I would pull the probe until you get the gfci set up. I use one of these

Also like I said, some voltage is ok. Maybe around 10 or 15v I would think. Getting into the 40s is too much

 

[92Miata]

I think the voltage reading is a red herring. DC pumps induce weird magnetic fields in tanks, and cause weird readings. If there aren't any AC pumps in the tank, its not a real thing. Put nothing but a bunch of MP40s in a tank and you'll still get a voltage reading.

These all seem like symptoms of corals not getting enough food, and you have undetectable nitrates and phosphate that's basically error margin from zero. You had a huge alkalinity spike (most likely because the corals stopped growing and uptaking calcium/alk) - and long term stress followed by a spike? That's a recipe for losses.

If you're going to run a tank that size bare-bottom with that much flow - you need way more fish IMO. Fish are the best coral feeder you can have - they take fish food and convert it into a constant slow drip of ammonia and phosphate.

And don't dump skimmate into your tank - it's a whole soup of who-knows-what - there are all sorts of chemical and biological processes going on in that cup that aren't going on in your fish tank. Either turn the skimmer off, or just remove the cup.

 

[nereefpat]

This tank is not on a GFCI so I will be taking care of that shortly. In the mean time, I have installed a grounding probe and stray voltage now reads 0.

If the tank isn't on a GFCI, it's actually worse to use a grounding plug. I would suggest to take the grounding plug out until you get the GFCI installed.

With the grounding plug in the tank, there is now constant electric current from your tank to the ground.

 

[jda]

I can tell you for sure that stray voltage can do this. Eliminate those things. I had a Sedra Pump in a frag tank cause all of my acropora to look like the skin was 'thin,' no PE and some death before I caught it. I could not even feel it unless I had my hand in the water right next to the pump. It took about a month, but everything recovered that did not RTN. The few softies, LPS and even some of the acropora did not care at all.

Put the heaters to where only the glass/poly tube is in the tank. I have my Ehiems to where the tops are out of the water. Get a different return pump.

Everybody has had a skimmer cup overflow and dump proteins back into the water - this is ugly and smelly but does not make healthy coral die. The N and P are fine. Neither of these cause death.

Never dump skimmate into the tank - there can be some really nasty stuff in it like hard metals that were bound to organics. Don't worry about undetectable N and p of 7 ppb is plenty - there is a paper on N and P in my signature if you want to browse, it but availability is what you are after, not residual levels, so if you are feeding those fish well, you are plenty fine.

 

[NeverlosT]

I agree with Mr. Miata and JDA.

your zero nutrients and alk swing could cause all of this. I personally would just stabilize ALK, get phos up to 0.02-0.06ppm and Nitrate to 10-20ppm and wait...

The high stray voltage is somewhat troubling. Honestly some tanks just have a good amount, like 12-18v of stray voltage, but 46V sounds pretty high.

 

[zachj7]

Yes, absolutely what others have said. DO NOT use that ground probe without the GFCI to interrupt it. You now have a constant current on your ground wire. Typicaly household wiring as you probably know have 3 wires, only 2 of which are meant to carry constant current and are insulated, the ground wire is not insulated, is exposed, and grounds and metal conduit/boxes, you name it. All this exposed wiring and connections carrying constant current is asking for a shock or a fire.

 

[nereefpat]

I agree with Mr. Miata and JDA.

Impossible.

Mr Miata is saying that the problem isn't stray voltage, and that Low N and P are the cause, While JDA is saying that stray voltage could be the cause and that low N and P are not the cause.

 

[92Miata]

Impossible.

Mr Miata is saying that the problem isn't stray voltage, and that Low N and P are the cause, While JDA is saying that stray voltage could be the cause and that low N and P are not the cause.

I think it's important to figure out whether these are AC or Dc pumps. It absolutely makes a difference.

If they're AC, the stray voltage is absolutely a problem. If they're DC, it's a multimeter problem that's causing that - the way they measure voltage just doesn't work correctly with the voltage induced by 'dc' motors.

 

[nereefpat]

I think it's important to figure out whether these are AC or Dc pumps. It absolutely makes a difference.

If they're AC, the stray voltage is absolutely a problem. If they're DC, it's a multimeter problem that's causing that - the way they measure voltage just doesn't work correctly with the voltage induced by 'dc' motors.

Yes, the 20 volts from the return pump concerns me..less so if it happens to be a DC return pump. The heaters would be AC.

 

[zachj7]

For curiosity's sake (I just couldn't believe that others were saying stray voltage is normal) I just measured my own tank. I have absolutely no stray AC voltage, 0.00V (Tank water measured across to ground, this involves disconnecting your ground probe otherwise you're just trying to measure voltage of a short which is always going to say 0V). I have a many AC pumps, heaters, vortechs.

When i first set up my tank 10 years ago, i discovered a heater i bought was broken, as soon as i put saltwater in there with that heater...ground probe into a GFCI tripped immediately.

 

[92Miata]

It's not really that stray voltage is normal, it's that the method a lot of multimeters use to measure AC voltage is really a shortcut and will pick up induced motor voltage and multiply it.

Take a good multimeter, set it to AC voltage and put it across a 12v battery and you'll get 0. Take a cheap one and you'll get 26-28v. Any motor in proximity to water induces voltage.

The question is whether his meter is reading is giving him a false reading, or he's got live AC in the tank, and until he knows which, 46 isn't a meaningful number.