CRS problems

[Jeff1192]

So I' have been running a small Fluval Ebi with CRS for a few months now. I was having a good amount of breeding and have 2 generations of babies in the tank. But a few days ago I started noticing the odd dead shrimp...always older ones. Not sure what is going on in there as the same thing happened to me a few years ago when I tried a CRS tank. The pH is good....6.6. No ammonia, no nitrites. So I started wondering about TDS. I do small water changes one a week or so but I'm thinking with evaporation the TDS woudl slowly go up as I top up more than I remove each water change. I had a kH test kit and I tested the kH and it's 4. I'm also setting up at 17 gallon tank to replace this one and it's just about ready for shrimp. I tested the kH it it and it's one. So could the slowly increasing kH be causing my problems? I'm thinking I'll pick up a TDS meter to make life easier down the road.

Thanks
Jeff

[Black_Rose]

I recently had a sizable die off in my main RCS tank.

While I was doing weekly 30% water changes (tank has embers and pygmy cories as well), I had forgotten to compensate for Ottawa's very soft water after a tank restart (swapped gravel for sand) and lost 40+ shrimp before I thought to check the GH.

I resumed testing of the GH and adding Seachem Equilibrium to bring the hardness level back up so they can molt properly.
There's only been a couple deaths since.

[Jeff1192]

So my TDS meter arrived today and I'm testing at 165 in that tank. Maybe the water doesn't have enough dissolved solids? Any ideas?

[ottguy]

A tds of 165 should be fine for cherry shrimp.  I usually aim for 180 to 200 for neocaridinia shrimp and and 90 to 120 tds for caridinia shrimp such as crystal and bee shrimp. Cherry shrimp can tolerate a wide range of tds up 400. But 180 is the sweet spot for cherry shrimp to breed.

[Jeff1192]

I am going to pick up a gh kit as the one I have is definitely expired. But I'm guessing from the tds reading that I'm pretty good for crystal shrimp. So still not sure what the random die offs are from.  It's a shrimp or 2 every couple of days it seems. All the other shrimp seem to be behaving normally.  I'm hoping the larfee volume tank I'll be moving them to may help keep things more stable for them.

[Jeff1192]

So to update this thread I think I have figured out the problem. This falls into the "sometimes the most obvious issue gets overlooked" department. I had not tested for nitrates as I assumed with the small bioload and all the plants in the tank that nitrates would not be an issue....well you know the saying assuming makes and a** out of you and me. I tested for nitrates last night and they were way to high.....so gonna do some small water changes over the next few days to bring them down. Lesson learned, even with low bioload and lots of plants I gotta keep on top of nitrates. I was doing really small water changes for fear that water changes might have been my problem (I was doing less than 10% once a week). So I'll have to increase the size of my changes on the new tank without getting too big.

Thanks for everyone's help on this one. Hoping this is the solution to my problem.

Jeff