Little update, I've bought a RO system. I'm transitioning the tank water to 100% RO, right now I'm using MgSO4 and CaSO4, 0 KH.
Last week I did 50% WC, GH is 7 (still 50% ro and 50% tap) and KH is 3.
The TDS from Ro unit is ~20ppm (scale500), I add GH 5 (3:1 ratio), I don't add any alkalinity due to aquasoil. GH 5 should give me around 110-130ppm of tds (+20ppm from RO)
This way I should be able to have CRS. But now I have some doubts.
The tank has cpd, ember tetra, otos and pygmy.
- embers (10) swim mid to top, rarely see them at the bottom. Should be safe
- cpd (8) are always at substrate level, they eat from the substrate
- pygmy (6) are safe, they ignore everything in the tank
The tank is 90g 110x50x60h, Dutch style inspired.
I want a clean up crew made by shrimp, I have 1 amano, I plan to add more friend to this guy (maybe 9 more, so 10 in total for 90g of water)
But what about CRS? Would they be just a snack for cpd or I'll be able to have a colony?
Photo of the tank below.
I would like to add Rummynose but they are hunters, and very active, maybe aren't even less safe for CRS.
Any specific reason why you want CRS in particular? The more robust Neocaridina species will likely fair far better in your medium hard water - where CRS do better closer to zero KH - and are available in a variety of colours. The fish will predate on some baby shrimp for sure, but if you start with a decent amount of Neo's (20-30) you should have them out-breeding any predation in no time.