Will Gh/kh Swings Of 4 Degrees Hurt Shrimp?

I received 10 red cherry shrimp from NY (I live in AZ) and have had 4 of them die over a span of two weeks. One of them died the day after I got them (likely stress), but then two died a week later, and then another a week after that.

I tested the water today, and in the tank the kH/gH is 5/8. Seems great. But then I also tested my tap water (after sitting for 24hr) and that kH/gH is 8/11. What I’m wondering is if the piece of driftwood I have in the tank is lowering the kH/gH and stressing the shrimp? The way I look at it, each time I change the water, I’m increasing the hardness with the tap water, then the wood would slowly lower it over the course of the week, then next water change I'm adding harder water again, etc...

Other paramerters: Ammonia is 0, nitrite is 0, nitrate is less than 5, TDS is 250, pH is 7.6, and temp is 74.

Thoughts? Could gH/kH swings be an issue? I’m wondering if I should remove the drift wood and Indian almond leaf (that would likely result in a higher kH/gH, but it'd be more consistent?). Could it also be residual stress from the move since it's been two weeks? It's also worth noting that one of the shrimp was berried upon arrival, and I currently have 5 babies in the tank that appear ok as well.

 

Before you start doing anything drastic can you prepare a normal water change but don't do the change do a gh/kh test then let it sit for 24hrs and test again and see it it stabilised to the lower readings

 

Before you start doing anything drastic can you prepare a normal water change but don't do the change do a gh/kh test then let it sit for 24hrs and test again and see it it stabilised to the lower readings

I do let my water sit for a week before using it in a water change (updated original post). Just to clarify, I just tested directly from the tap and the kH/gH was 7.5/11, and then I tested water I've had sitting out for several days and it was the exact same kH/gH of 7.5/11. (I say 7.5 because the color just barely started to change color at 7, and then I added another drop and it fully turned).

 

a small swing like the should have no impact on the tank to a degree of killing them, big swings then yes you would have a problem GH becomes a problem below 5 and it causes moult issues which can lead to death, if the didn't acclimate well it can show a few weeks down the line and yes kill them when they try to moult, the first died the following day probably a forced moult, the next 2 when they tried to moult further down the line and the third a week later, your new born are your next generation these were born in the tank and are acclimatised through birth hopefully the others will come through the longer they go and get through that first moult the safer they are, it's not uncommon to loose a few like this, yo could try taking the wood out the other thing to consider is if your substrait is buffering down, what's not clear to me at the moment is your PH & KG are connected and move up and down together but they don't affect the GH so why the two are moving together says something is altering your GH but not to a point of killing shrimp, these values often change in the wild when you get rain it will never be the same albeit we try to keep as stable parameters as possible for the conditions we keep them

 

richie.p Thanks so much for the thorough response, it's a big help. This may eliminate my biggest worry that a gH/kH swing of 3 or 4 degrees could be killing the shrimp each week during water changes (I wasn't sure what would be considered a "large" swing). It's a small tank (3 gal), so I wouldn't be surprised if the driftwood is what's altering the gH. Soil is mostly Eco-Complete with a bit of Seachem Flourite which I read shouldn't alter gH. I've had several successful molts, so I'm hoping it's a stress/acclimation issue and that the remaining adults and new borns do well. I will also try more frequent but smaller water changes for a while.

 

It much more difficult to keep stable perameters in a small tank I didn't realise it was a 3gal. Almond leaves naturally alter ph and 1 leaf is enough for 15gls so a 1/4 of one leaf is ample so there lies your answer to low ph, the deaths are probably related as I explained
How big a water change do you do ? 15%-20% weekly is enough and with a small tank it important to get the water as close to tank temp as possible as this will shock shrimp with a result in death which yours are showing signs or

 

I did have a full almond leaf in the tank for a while, but yesterday I actually removed most of it and left about 1/4 of it in the tank (I did soak it for a week before I put it in the tank to remove much of the tannins). My pH of 7.6 is actually similar to tap (tap water pH is 7.8). I keep the aquarium at room temperature, and as mentioned I let new water sit out for a week, so when I do water changes it's the exact same temperature. I'd say my current water change is about 25% (I probably remove 15% to 20% but with evaporation I tend to refill about 25%)