System Crashing??

[alabama reefer]

Here is some history and hopefully I can get some advice on what else I need to be looking for: This tank has been up and running for 4 years. It is 150g reef system with 225lbs of live rock. I had a hair algae bloom about 1 month ago and noticed some of my coral start to decline but still alive (frogspawn, hammer, zoanthids, bubble, favia brain) corals not affected are duncans, leather, open brain, mushrooms.. I have done 10% and 25% water changes in the last month figuring it must be some trace elements that might be missing that the corals needed. Now about 10 days ago I lost a blue-eyed tang that was a picture of health the day before(eating and no visible issues) been in there for over a year. Three days later I lost a Naso tang that I've had for 3 years same way no warning signs. Yesterday I lost a foxface lo (2 years in tank) same story. These fish died fat and eating. I am at a loss and don't know what is going on?? Here is what I can tell you. The only thing that has been added to this tank was a heater about 3 months ago(could electrical current be causing this) no livestock has been added in 6-7 months. Here is what I have checked:
Ammonia-0, nitrite-0, nitrate-10, ph-8.3, temp-78°, sg-1.025, alk-10, calcium-440. I am running 4-110w vho's(bulbs 6 months old) and 2- 400w mh(bulbs 4months old) two koralia #4 ph's and one mj 1200 sure flow modded ph. Sytem has a 40g sump and asm g3 skimmer. I know this is long but trying to give useful background so maybe I can get some helpful advice.
Thanks in advance!

 

[speg]

Do you have multiple test kits? I suggest taking a sample of water to some LFS's in the area and letting them double check your results first. It's hard to say where else to start with the information you've provided; not that the information is lacking.

 

[alabama reefer]

I have tested the water with my kits and a friend of mines kits with identical results. I also want to add I have tested my RO/DI water and that two other friends use the same water with zero problems.

 

[speg]

It sounds like something unusual happened maybe a month ago then that caused the algae bloom. Overfeeding? Lights too old (bulbs)? Different salt mix?

 

[beaslbob]

sorry for your losses.
not much I can help you with especially with only losing 2 of the fish and showing no signs of distress.
perhaps some kind of toxin of the water changes themselves caused the fish deaths.
Sorry I couldn't help
my .02

 

[mrdc]

Good luck. Mine crashed after about 4 years and I was never really able to figure out what happened. I have some theories but that is all. I was able to save some coral by putting them in a friend's tank but lost everything else. I quit the hobby for about a year before I decided to try again.

 

[alabama reefer]

As stated in the opening the bulbs are not to old. I feed every other day but it could contribute to the algae. Hair algae is not killing my fish. Surely someone can offer something I haven't thought of?????

 

[ibanez]

Could have been something in the salt mix, but it doesn't make sense that not all your fish would die. Could have succumbed to some parasite that has been dormant, or in their systems for a while.

 

[reefaholic33]

Have you done any cleaning like carpet shampooing or something to that affect? Anything at all might lead to some answers. Any chemicals at all around?

 

[ibanez]

Or, maybe it was due to obesity related complications. Bad food could be another possibility. Sometimes fish just die, I have heard that they can have internal organ failure for no detectable reason just like humans can, and it could have been just a coincidence.

 

[alabama reefer]

No chemicals have been around the tank. I think contaminated salt mix would be a stretch since all my other fish are alive but then again the ones that died showed no signs of stress that I picked up on. Because I lost three fish and half my corals are fading away it makes me think it is something in the water chemistry but what?? Could electrical current cause these problems??

 

[6stokes]

Do you run carbon once in a while? Your RO/DI unit won't always catch all of the clorine or cloramine. Also, do you have a deep sand bed? If you stir up the sand in a deep bed it will release toxic gas that will kill a fish or two within 24 hours.

 

[6stokes]

Forgot to address your electrical question. I'm not sure stray voltage will actually kill them unless it's pretty high voltage, but it is extremely irritating to them and could cause stress. Sounds like a jet airplane taking off to them 24/7. Do you have a way to check it? If you don't have a grounding rod, I will almost gaurantee that you'll have some stray voltage.