Mystery Shrimp Deaths

[The Collector]

Hello all,

 

First time poster here, but I'm hoping that someone can help me solve my shrimp death problem. So without further ado...

 

I have a 20g tall with matten filter fueled by a Tetra Whisper air pump. The tank is lit by an Aqua Worx Orion LED with a dimmer set very low...just enough to grow some anubias, christmas moss, and giant bucephelandra in the tank with a single piece of driftwood, along with some green spot algae here and there. The timer is set to an 8 hour photoperiod and then off for the night. The tank is bare bottom, with two acrylic square containers containing Shrimp King active soil that I am growing the aforementioned plants in. There is a heater but it rarely comes on as I have it set to 72 and my house temp is an almost constant 74. There are no nearby windows or air vents to cause drastic temperature fluctuations.

 

I set the tank up and seeded it with bacteria from the filter of a separate, healthy aquarium last October, then let it cycle all winter. I use distilled water from the local grocery with a TDS of 0 prior to re-mineralizing with Brightwell GH+. I titrate up to a GH of 5, which gives me a TDS of about 100. Ultimately, my parameters were this after cycling, from an API master test kit:

 

Temp: 72-74F

TDS 90-110

Gh 5-6

KH 0

Ammonia 0

Nitrite 0

Nitrate <20

pH 6.0-6.4 (yellow-green color)

 

 

In March, I added 10 crystal red shrimp that I purchased from a reputable source. I drip acclimated them over the span of several hours. I lost one overnight immediately, and I blamed it on stress from shipping. I did retest my parameters, which were nearly identical to the above.

 

Over the next few days, everything seemed fine. I fed them 1 stick of Shrimp King Complete on a glass disc, which they showed little interest in, and then removed it after two hours. All of the shrimp seemed to be content grazing on algae and exploring the tank. I did a 10% water change, matching parameters nearly perfectly, after a week. 

 

On the rare occasion I have to top off the tank, I use distilled water I buy from the local grocery store, and drip it in over about 2 hours. I use Seachem Prime with each change or topoff.

 

Once a month, I clean the algae off the front glass only, just to promote viewing, and leave the rest of the glass with algae to allow for something for the shrimp to eat.

 

Despite everything seeming ideal, over the last two months, I've lost approximately one shrimp a week, without warning. I now only have two left. When I recover the corpses, I don't see anything overtly strange about them- no obvious fungal growth, parasitic infection, etc. Furthermore, at no time did any of the shrimp show any signs of breeding, indicating stress, I suppose.

 

Up until now I've only ever kept Neocaridina, so I suppose I could be missing something obvious. But, I did my research and thought I had everything set up properly for Caridina. Anyone that can offer any advice to correct this problem would be greatly appreciated.