Snazzy 12g Nano

[Snaz]

So it has been almost a week since I picked off the last visible nudibranch and I have not seen any eggs so I am hoping this problem is behind me.

I am having issues with my dKH falling to 5.7 from 6.7 within 24 hours. I did a water change today which brought it up to 6.9 but it is dropping again. I can bring it up with some Arm&Hammer but I guess I need to sort out a dosing routine. Time to buy a calcium test kit. Can I cheap out with Ca test kit or buy Salifert?

My large orange/green Echino is getting too big for this little tank, time to list it for sale I think.