red serpent has a hole

[fishy1]

Hi :help:
I have a 46 gallon tank that has been up for almost 2 years.
My salinity is 1.022
nitrate and ammonia are 0
nitrite is 10
PH is 8 (this I have been keeping an eye on because it was ranging from 7.8 to 8.2; I bought Kent PH this time and it keeps it higher, but it still goes down to 8).
temp 81
I change 1/4 of the water on a weekly basis.
I added 7 pounds of sand almost 2 weeks ago and my inverts all got slow and weak/limpy. The store told me they would be okay and the sand increased the PH level, which threw them off. That was last week and I have been monitoring since and bought a Kent invert kit to increase the levels of calcium, iodone, etc.
All of my small crabs (blue and red hermits) and my sand sifter died almost immeadiately; I have not seen my snails either. I also had a sally lightfoot (died 2 days ago) and a shrimp who died 4 days ago. All I have left is a spiny sea urchin, who looks normal, and a red serpent who got a whole in his body last night. Now his internal organs are showing. it's about 1/8th the diameter of his disc....

Number 1, WHAT IS GOING ON????? These have been my readings for well over a year now!
Number 2, can I save him or should I save a prolonged agonizing death and kill him?????

I really don't understand and could use advice. It must be something I'm not testing in the water???
There aren't any fish in there.
THANKS SO MUCH!!!!!!!

Fishy1 :happyfish

 

[newatsalt]

The same happened to my black brittle star....Beth is really good at this one......
if you want to read my old thread - do a search and type in "biological filter" and it is the one started by newatsalt. Good luck

 

[fishy1]

thanks!

 

[ophiura]

I need to know more about the parameters and history here. What is your alkalinity?
This is for sure:
IMMEDIATELY STOP ADDING ANY PH ADDITIVES UNTIL YOU KNOW YOUR ALKALINTY AND CALCIUM.
Your pH at 7.8 is NOT a problem if it is stable, but adding these pH buffers CAN CAUSE SIGNIFICANT problems if you are not monitoring your alkalinity and calcium levels!
What are you using to test your specific gravity (it is, IMO, much too low for many of these invertebrates...if you use a hyrdrometer, when did you last soak it in white vinegar?).
I would not add iodine unless you have a test kit for it.
What sort of filtration and skimmer do you have? How long have you had this brittlestar? Is there damage to the arms? Is it still hiding? Is it still interested in food?