Invert tank losing consistent deaths

[BurlyWizard]

We've got a Fusion 25 gallon lagoon invert tank that's been up since about March and it's seeing just unexpected, but consistent death among the inverts. We see a pretty consisent pattern of death: 1 thing has died every 2-3 weeks. Parameters are unchanged. Water changes are less common, but mangrove and some lingering cyano keep nitrites down. Feed every other day or so. Everything that has died has been found whole, not attacked, discolored or eaten. They all seem like flukes, but they just keep happening. RODI water all the time. Tank was seeded with mainly dry rock and 1 piece of LR from LFS, then 2 bags of Live Sand. Never seen any aggression toward any tankmates except some of the shrimp chasing the others out of it's cave if it wandered in unknowingly. Basically

Parameters:
- Tank set up since March 1
- Temp: 79 degrees consistent (Using 2 heaters and temp does not fluctuate from what I see)
- Specific Gravity: 1.025 with an ATO, so no fluctuation there either (match perfectly on water changes)
- PH: 8.1
- Nitrates: Near 0, but about 0.2ppm
- Chemipure blue changed every 3 months or so, but never seen parameters spike
- Don't test for much else based on the simplicity of the tank

Critters we've lost:
- Skunk cleaner
- Emerald crab (2x, about 2 months apart)
- Porcelain crab
- Camelback shrimp (2x, spaced out a bit, one jumped)
- Sexy shrimp (2x)
- Halloween hermit
- Couple cerith snails

Current tankmates:
- 3x Azure damsels (been in tank 3-4 months)
- 1x Camelback shrimp (came in with the 2 that died, this one has hung about 4 months)
- Couple cerith snails
- 1x sexy shrimp (came in with the 2 that died, been in about 2 3 months)
- 1x peppermint shrimp (added last week)
- 1x skunk cleaner shrimp (added 2 weeks ago)

Basically post-cycle, we added something every few weeks or so, but the deaths have been spread out over several months, never in a big "wave" after adding something new. I really don't think we spiked ammonia at any point, plus the cyano and mangrove are likely helping keep that in check. We just lose a shrimp or crab, then a few weeks pass and another one turns up. Without any evidence, we thought it was "just one of those things" but now it's a pattern.

Any help is appreciated, we're clearly missing some piece of the puzzle here. Thank you!

 

[outhouse]

Your suffering from a new tank not seasoned well. Id would be doing major water changes as much as you can safely.

, we added something every few weeks or so,

what are you adding? you should not be adding anything

I really don't think we spiked ammonia at any point

you dont have to, if the tank cannot handle the bio load, then your getting some, and just a little is deadly

plus the cyano

Thats what is telling me your water is crap, flush it all out, but dont kill your nitrifying bacteria in your sump or you could cycle again.

 

[BurlyWizard]

Thats what is telling me your water is crap, flush it all out, but dont kill your nitrifying bacteria in your sump or you could cycle again.

I appreciate your candor. Can you please help me understand what's leading you to that conclusion? We took the cycle slow, we tested ammonia, nitrite, nitrate and I surveyed this forum several times and unanimously heard that the tank was cycled. We added a few inverts at a time, but as they are considered clean-up crew, I was told they we either "negative" in terms of bioload as they clean up waste, or not serious contributors, as a fish is. We watched the behavior, everyone got along, all were/are molting, and nothing has died within a week or 2 of adding, so we assumed it wasn't a bioload problem. We waited and put fish in last, and they have been doing great.

The tank is now 6 months old, and from all the research I've seen, cyano is typical in new tanks, but not necessarily evidence of "crap water" but overfeeding, lights too long, or high nitrates. The cyano we do have is not an outbreak, but some light patches around the sand. We are dialing in the lights to balance feeding the mangrove but also not having them on too long. I mentioned the parameters, and nitrates are very low, reconfirmed with the LFS. When we have added things, I tested ammonia/nitrites and they remain 0 from what I've seen.

Is there another parameter I should be testing to track the "crap" status of my water? And more specifically, what makes it crap?

 

[outhouse]

Can you please help me understand what's leading you to that conclusion?

You dont need to test. Animal loss is solely due to poor water conditions. Cyano can happen in decent water, but its usually poor water conditions. And the reason it happens in new tanks is poor water quality, because the tank cannot process efficiently yet.

so we assumed it wasn't a bioload problem.

it really takes a while to seed a tank with enough to handle ups and downs, A new tank that has recently cycled, can only handle a very small bio load, and if you over feed or add to much you can surpass the tanks ability to deal with it.

I tested ammonia/nitrites and they remain 0 from what I've seen.

They can still test 0 it does not mean they were not there in small amounts long enough to kill things before becoming undetectable again.

 

[Brent Bohannon]

Have you checked for copper?

 

[Mr. Mojo Rising]

Thats really a lot of critters, with so many critters, I think you're bound to see some aggression among them as they try to establish territory.

Are you sure they are all being fed adequatley? Some are more aggressive eaters than others and might not leave enough food.

Also, sexy shrimps and porcelain crabs do better in small groups than they do alone.

Also, crabs are bad, I would suspect they probably killed a few of your inhabitants before dying themselves.

Anyways, I'm completely guessing. PS - an invert tank sounds super interesting, good luck!