Brittle Star dying, keep flipping hime over or let him die?

[sinner's girl]

Should I keep filping him over, or let him die?
A few weeks ago when I went to feed my stars (wed, June 29th), I found one was dying . I did a water change and tested the water. It was okay. The other star is fine-active, eating, and not dying. There are no fish in the tank, just some hermits.
The Brittle star lost three legs, and his other two are small. One leg fell off, I'm not sure what happened to the other two, I guess they shrunk because I didn't find the legs. He started flipping himself upside down Tuesday last week, about 6 or 7 times now, three times just today. I flip him back over. I think he’s trying to kill himself. Last time this happened he didn’t flip himself over, he went into the rocks and just hung out until he was better (moving the tank caused a spike and he lost parts of his legs…after 6 months he was bigger than before). He's not eating, but he didn't eat last time for a long time either.
Should I just leave the Brittle star alone and let him die? Or should I keep flipping him over? Is there anything I can do to help him?
Thanks, I hate to see him die, but I want what's best for him. Is there anything I can do?
75gl tank, been up for one year in current location, was moved from the living room last summer. I've had the stars since I registered here. Lots of lr (1/4 the tank). Salinity 1.023, temp 80-82 (78 in the winter, I have trouble fighting the heat in the summer, I can't get it below 80 unless the a/c is below 80). I feed shrimp once a week about 1/3 to a half for each star (they won't eat more than this, I've tried feeding more than once a week and they ingore it). Brittle star hasn't eatten in a month. But like I said, last time he wouldn't eat either.
Edit, I just read that SG 1.023 is low for inverts. That's where I keep it (for the past four years). Actully, it's been a bit lower lately, but still within range, or so I was told, for about four days it was at 1.019 (I ran out of salt and the local store didn't have any). Where should I keep the SG?

 

[sinner's girl]

He's flipped himself over again. Can anyone help? When I flip him back over he moves a little bit. I can't tell if he's trying to walk and falls over, or if he wants to flip over.

 

[ophiura]

1.019 is FATAL or at best EXTREMELY STRESSFUL to most echinoderms like brittlestars. There is an individual tolerance that comes into play, but that is definitely not good, IMO.
The specific gravity should be 1.025-1.026. 1.023, IMO, is too low.
This is the first thing to be addressed, though unfortunately for the sake of your other inhabitants it can not be done rapidly. You can start by topping off the tank with saltwater instead of freshwater. But my bet at this time is that the specific gravity is getting too low.
What is your pH and alkalinity?
You can isolate the brittlestar in a container such as a small critter carrier or something that has a vented top so that water can be exchanged easily. Put some small bits of rock in it. You could probably even take like a gladware container and use a whole punch to punch several dozen holes in the top. This isolates the star, and prevents critters from picking at it.

 

[sinner's girl]

I've kept sg at 1.023 for the past four years, I was told that was ideal, of course that was when we had fish also. So both stars have in 1.-23 SG since dec 2002. It was only 1.019 over the 4th of july, and I brought it back up over a couple of days. He was acting fine then. He didn't flip himself over till a week later. Of course I will bring it up, that's not a problem.
"prevents critters from picking at it." There are no critters picking on him. The serpent star leaves him alone, and the hermits (I only have a few) are in the lr (which is all on one side of the tank from when I did a water change). I haven't seen a hermit bother him in the past few weeks.
Should I still isolate the brittle star even if no one is bothering him? Will this prevent him from flipping himself over?
Ph looks about 8.4, I can't tell alkalinity, it's blue on the strip, the highest the chart goes is 240, the only one I could find was for a pool. I can attempt to have the LFS check it tomorrow. How do I adjust alkalinity or ph? Where should alkalinity be?
Thanks
It's amazing how much infor one can forget over the years, when one doesn't use the infor. (we thought we were moving this summer so when my fish died two years ago we didn't replace them, now we don't know when we are moving, but we still haven't added anything (except a few hermits) to the tank in two years.)

 

[ophiura]

Many of these critters will not show ill effects of salinity shock immediately. This is why many seastars die within a month of acclimation and not immediately. Their metabolism just works at a very different rate, so it would not be surprising if the issues started after. But all in all that salinity is quite low for inverts.
But as a demonstration of how severe a salinity change can be, you can see mass mortality of seastars in bays after heavy rains. Just the run off of the water can cause such severe shock that thousands of starfish will die from it. They are really intollerant of salinity change....which is why that mantra of "stability" is so often heard. While it may have been getting by at 1.023 for quite a while, which is marginal but still tolerable, IMO, the drop to 1.019 would really have been a severe stress I think. At least that is the obvious problem at this time.
With this being said, I am assuming that other parameters are in order, and that there are no other obvious issues (temperature spikes, etc) in the tank.

 

[sinner's girl]

Okay, I will add saltwater now, and I will bring the SG up. I just wish I knew it was too low before now. I knew the 1.019 was too low, I was freaking out, but I ran out of salt and the lfs was out (don't ask me how or why a fish store runs out of salt).
The temp stays at 80-82 in the summer (and has been there for the past few months), 78-80 in the winter, one day last week my husband turned the a/c lower and the temp dropped to 78 for a short while. Everything else is fine when I tested on the first. I'll have everything tested again tomorrow.
Thanks for your help! :cheer: