Thank you both,
Yep I've lowered my heater setting to 24C (which should give me 23C). Not sure why I had it up at 26C in the first place, i think because my thermometers designates 25/26 as a green spot which i associated with being ideal but a quick google search would've told me otherwise.
The stones have been removed and cattapa leaves added but i havent done a water change yet as I had just done one a few days ago but I will do a small one tomorrow to begin that transition to a lower PH.
I think it is moulting related issues as well based on that picture. At least we don't have the fish mangling the shrimp, so we can diagnose it properly. Thanks for moving them into a breeder box, even though it's a pain catching them.
If those stone have been removed, the water parameters should start improving. But the symptoms with the shrimps will continue for a big longer.
I know you don't have RO water yet, but have you done a water change since removing the stones? Even with your tap water parameters, it should help a little with moving the tank's water parameters in the right direction.
Canberra is about to get some rain on Friday. Maybe set some buckets out to collect some rain water and use that for water change.
Simon also has a good point with temps. We are in winter here, so moving temps down to 22-23 should not be a problem. I keep my CPDs at 23degC. So your's should acclimate well to that temp too. Plus it saves on electricity.
Sorry to hear you are still having this problem. I think it is a molting related issue, and the water isn't quite right if they are trying to get out.
The trouble with tap water is you don't know what is in it so you will be better off slowly transitioning to RO remineralised when you get the new unit as that will be ideal parameters always - tap water can change as well from time to time and you won't know. Going back to the original post, the parameters are only just acceptable but out of 'sync' a bit, ie KH uppermost limit, GH lowermost limit etc. I don't know how hot it is where you are but if you can get that temperature down to 22-23 that would be better as well as again, you were at the uppermost limit!
I hope you get the equipment before all the shrimps die off!