Shrimps aren't very high bioload so you should probably reduce the weekly water change to no more than 25% and the new water will need to be dripped into the tank over many hours. I haven't used salty shrimp but I have heard it usually comes out about 6.8 so I don't think that is a problem. It is more likely to be you are changing too much water which has that PH difference of 1 may be too much for the babies to cope with. Lava rock won't alter the PH/KH so thats fine.
Just do 20-25% weekly water changes, adding the ew water with a driper and I think you will be fine. I would probably get some baby shrimp food as well and that will be a powder,, so use a pin, dip the tip 2-3mm in to the tank quickly to wet, then in the powder and then swirl that in the tank so it spreads around. It is a fairly small tank so there may not be quite enough natural biofilm (caution not to over feed though).
Sorry, yes you are right. I have tropica powder Soil with Taiwan Bees. They are all healthy, no one is dying, buy my shrimp babys die off after maybe 2-3 weeks 😕 The only rock i have inside my tank is lava rock.
im asking, why the PH is rising, because im putting RO water with only GH salt inside the RO water. Still the PH is rising to 6,8 PH after maybe 24-48 hours. Im little bit concerned, because my RO Water has maybe 5,8 PH? and the difference is too high to raise that fast. Maaybe thats killing my baby shirmps? The high difference. But i dont want to put any KH anymore in my Waterchange water.
Thank you so much for your help 😃
I assume you are using a (PH buffering) soil substrate and keeping caridina shrimp? A PH 6.8 and KH 1 is fine for usual caridina shrimp! Are the shrimp dying? Usuallly rock can cause PH/KH to increase but I assume you don't have any of that as you don't list that as in the tank? If you are using soil, it may have absorbed some of the KH and is slowly releasing it but that should reduce over time and if you only have KH1 that isn't a problem - I don't think you can actually measure KH 0 anyway with the usual test kits as each drop is +1 KH? It is possible to get smaller reading than 1 by altering the volume of water you test, double the water (10ml) each drop of tester fluid is then half a KH, double that again (20ml) and each drop will be quarter of a KH, but it isn't really necessary and wastes a lot of tester fluid you could try it once though if you want a more accurate idea of exactly where the KH is, not to the nearest whole number.
I may not have grasped what your actually asking and I don't see any problem from the post but do feel free to ask again if I haven't understood?
Welcome to the forum by the way and hope you enjoy it!