URGENT all new fish dying

I have a 940 gallon saltwater tank at my work. When I first took on the job to fix the water paramaters and restock the tank we had
1 domino damsel
5 yellowtail damsel
5 tuxedo damsel
2 cucumbers
2 cleaner shrimp
1 green chromis

all of these fish are still alive and seem well.

I did water changes for 3 months until I thought it was in good condition, so 6 days ago we purchased:

1 porcupine pufferfish
2 cleaner shrimp
3 clown fish
12 green chromis
1 angelfish
1 anenome

now 6 days later there are only 6 of the new chromies left, one clown fish is gone the other one is currently dying. The clown fish were always hiding in the anemone and I never saw them eat ever, also haven't seen the pufferfish eat.

Obviously there must be a big problem I'm not seeing? Here are the parameters:

kh - 240
ph - 8.5
nitrite - 0
nitrate - +200 (I tried to bring this down with water changes but it never made a difference, I read that nitrates usually aren't much of a problem, I hope that's not false)
ammonia - 0 (test kit is hard to read but I am quite sure its 0 after months of water changes)
salinity - 1.021
temp - 77


The tank has tons of live rock, can't remember exactly but I think its 500lbs. It has 2 protein skimmers and I have another one ready to install. It has a sump and carbon and sponge filtration.


I'm really worried now that already 6 chromies and basically 2 clown fish are dead, and I really don't want anything to happen to the puffer. Angel and shrimp and all of the other old fish are fine. Any advice would really help, thank you

 

nitrate - +200 (I tried to bring this down but nothing seemed to work, I read that usually it wasn't much of a problem, I hope I'm not wrong)

*Points* There's your problem!!

I'm not a Saltwater person, but while you're waiting for one to turn up, if you could list the various hardware, amount of live rock etc. The more details the better. It will help others to help you.

Edit: Thanks for that, it will help. Hang tight, I'm sure someone with Saltwater experience will be along soonish.

 

Hi, sorry you're losing fish.

1 porcupine pufferfish

Puffers are not reef safe, and can and do eat smaller fish, crustaceans and the like.

3 Clown Fish

It's generally not wise to try and keep more than a known pair of clowns in a tank, they can fight amongst themselves.

kh - 240
ph - 8.5
nitrate - +200
salinity - 1.021
temp - 77

KH is a little high. 8-12dKH (140-214) is a normal range.
pH is a little high, but not too high 8.0 to 8.6 is generally ok, most run around 8.2/8.4
Nitrates are a definite problem, they should be below 10ppm, closer to 0 the better.
How were the fish acclimated? My guess is they are suffering from nitrate poisoning, having come from a much 'cleaner' environment, into a highly toxic environment. Are the fish lethargic and/or resting just below the water surface?

Salinity is a little low, fine for a FO/FOWLR, but for a reef, you want to be around 1.024/1.025

What test kits are you using?

How much skimmate are your skimmers pulling out?
If they're functioning correctly, I'm surprised to see nitrates at dangerously high levels (30ppm can can limit growth, and affect the immune system)
You might find the skimmers work better if you bump up the salinity.

What are you using for top-off water? Tap water could be introducing nitrates.

What is your source for salt water?

 

Also, did you quarantine the new fish?

 

I use API test kits. I don't know how much the skimmers should be pulling out but it doesn't seem like that much. I usually empty and rince it once a week. I tested the tap water and it wad 0.25 ammonia and 0 nitrate and nitrite. I use Prime to condition the water. For my saltwater I use the tap water and "instant ocean" salt which I let airrate for 6 - 12 hours. When I introduced the fish I let the bags float for about 20 minutes then slowly added tank water for about 45 minutes.

I will do a water change and bump up the salinity.

The puffer literally just sits on the bottom and won't eat. It would be so difficult to remove him as its such a huge tank and we don't even have nets that long. The old fish swim around like its no problem as well as the angel. The single clown fish that is left just hides in the anemone, he also won't eat.

I am going to try the vodka method for reducing nitrates but I read that it could take up to 2 weeks so that probably won't help. Its hard to get things out here because we live int he middle of nowhere, closest fish store is hours away.

What should I do, I feel really bad for introducing these fish is the problem is the nitrates...

 

Do you have any macro algae? Doing a meaningful water change on a tank that big would be a huge undertaking but helpful. Adding a bunch of macro algal species should help to bring the nitrate levels down.

 

I use API test kits. I don't know how much the skimmers should be pulling out but it doesn't seem like that much. I usually empty and rince it once a week. I tested the tap water and it wad 0.25 ammonia and 0 nitrate and nitrite. I use Prime to condition the water.

Hi,
The ammonia in your tap water won't be helping the nitrate situation, but is probably not the cause.
If you can switch to RO/DI or distilled water, it would be much better, but I understand the volume required may present challenges.

I will do a water change and bump up the salinity.

Do so carefully and slowly. Never add salt directly to a stocked aquarium. I would pre-mix and use as your top-off water until the salinity reaches the desired level.

FYI: it's going to take about 47kg/103lbs of salt to bring 940 gallons from 1.021 to 1.024

The puffer literally just sits on the bottom and won't eat. It would be so difficult to remove him as its such a huge tank and we don't even have nets that long. The old fish swim around like its no problem as well as the angel. The single clown fish that is left just hides in the anemone, he also won't eat.

IMO - the puffer needs to go.

I am going to try the vodka method for reducing nitrates but I read that it could take up to 2 weeks so that probably won't help. Its hard to get things out here because we live int he middle of nowhere, closest fish store is hours away.

Be careful with this method: you need to build the system up to it. It will help, but as you've found, it takes time to work. You may find you need to go to a Vodka/Sugar/Vinegar mix to get great results. Too, depending on the phosphate level, this method may or may not work, there is a direct relationship between carbon, nitrates, phosphates.

What should I do, I feel really bad for introducing these fish is the problem is the nitrates...

How much Prime do you have? You could dose the tank daily to detox the nitrates while you work on bringing them down. Prime can safely be used up to 5x the standard dose.

Just as a side thought - what type of anemone is it? Seems odd that a 'nem would tolerate high nitrates like it is.

 

I honestly have no idea what kind it is. It was the cheapest one they had, 90$. its pinkish grey, and it totally seems like it's doing fine.

I'm going to try the prime, and vodka method, and see if maybe I can get some macroalgae, but I doubt the closest fish store would even have it. Will check though. Thank you !

 

OK, slow down.

With nutrient export, you need to pick one method, and stick to it. Using the Vodka method can starve the macro algae.

Your options for nutrient removal are:
1) Refugium with Macro Algae and deep sand bed (DSB) - the DSB creates an anaerobic environment for nitrate consuming bacteria to live.
2) Chemical removal using Nitra-sorb or similar
3) Carbon dosing; vodka, VSV, NO3O4-X, bio-pellets etc
4) Lots of water changes.

 

Water changes unfortunately have not made a difference for me with the nitrates yet. I would love to go with the simple route of chemical removal but with a tank size this large I would need so much and I think it would be quite expensive, I will take a look tomorrow just in case.

So let's say I am able to get my hands on some macro algae, then which do you think is better and would work quicker, that or the vodka?

And can I still dose with Prime at the same time? From my understanding it simply temporarily detoxifies the water for up to 48 hours. Can I dose every 48 hours or is that not good to do?