if you use RO water, then no need to even do hardness test.

tap water of 70 and your tank of 180 TDS reading, but you wont know what's in it, if you didnt use RO water.

yeah, time to change a filter. but for shrimp, it is good to use sponge filter, always recommended.

good luck and all the best!

maybe share a picture would be good~!

If you are using RO water and only add the GH by yourself, then TDS 150 is fine.
if you are using tap water, you dont know what is in your 150 of TDS.

PH no need to worry, generally our tap water is fine, and since he is using soil, it would buffer the ph a bit. plus neocaridina is okay in those condition.

if he only keep shrimps of 10 pcs of lower, don't even need to feed, at most feed once every 2-3 days would suffice.

suggest not to buy ghost shrimp. just get cherry shrimps to start with will do.

you also dont know what kind of bacteria or disease might be carried by those ghost shrimps which you might introduce into the tank and subsequently you put your neocaridina shrimps in it, they might get affected. that's why i suggest to go straight with the shrimps that you want to keep.

if you cycle your tank properly, then I do not see much issue.

By the way, I have a 3ft rack of shrimp system tank (with filter) for sale, let me know if anyone is interested, we could discuss further.