Fish keep dying.

[drud0616]

I have been losing a lot fish lately and am not sure what is precipitating this.
3 days ago I lost my royal gramma.
Last night I added Kalkwasser and vinegar to my reef tank (as I have done several times in the past). This morning I woke up to two more dead fish (purple pseudochromi and flaming angel).

Here is a summary of my tank:
55 gallon (running for 7months)
Reef octopus HOB protein skimmer
Approx 40lbs of life rock and 3 in. Deep sandbed.
RO/DI Water mixed with instant ocean
Feeding: omega one flakes and seaweed pellets daily. Coral frenzy or Frozen Cyclops feed every other day

Water parameters:
Temp: 80F
Salinity: 1.026
pH: 8.3
Ammonia: 0
Nitrite: 0
Phos: 0
Nitrate: 20
Alk: 11.2
Ca: 410
Mg: 1580

Fish (currently):
Yellow tang
Blue hippo tang
2 clowns
Green chromi
Mandarin dragonette

Coral:
Jasmine
Kenya tree
Bubble coral
Plate coral
Frogspawn
Chalice drag
Torch coral
Rainbow ricordea
Star polyp frag
Brain coral frag
Candy cane frag

I can think of a couple of culprits, but figured you guys can help me narrow it down.
1) My tank temperature has been fluctuating from 78F to as high as 88 at one point. Mostly averaging around 80F.
2) My tank may have been overstocked. Stressing the fish out.
3) I dosed the Kalwasswer and vinegar wrong? I used 4tsp Kalk and 25ml of vinegar in 2 gallons of RO/DI water

If you guys need any more information please let me know. Thank you in advance.

 

[veselym]

what was the PH spike from adding the kalk? if it was greater than a .02 rise then that could be the cause...also 2 tangs in a 55 is a bad idea and yes you are overstocked

you really need to stabilize your tank, stop the tank temp fluctuations and get the nitrates down

 

[drud0616]

Hmmm good point Veselym. Just a correction on the pH parameter: Yesterday prior to the addition of Kalkwasser the pH was 7.9 and this morning it was 8.2

 

[veselym]

overnight fluctuations are normal...if it raises more than .02 in a seconds time it is bad

do you dose the kalk all at once? stress is a very likely culprit though

 

[drud0616]

I mix it 4 tsp of kalkwasser with 25ml vinegar in a two gallon container and slowly drip it (about one drop per 1-2 seconds until the container is empty. I never put the any of the leftover kalk from the bottom of the container.