Planted shrimp tank slowly unbalancing?

[rnn]

This is a little long, apologies in advance!

The problem: My tank is slowly unbalancing.

tl;dr: My KH and pH have both lowered over the past couple months; my java ferns and christmas moss have totally died over the past couple months; my shrimp have been disappearing over the same timeframe; the snails are going wild; duckweed and floating stem plant are thriving; my nitrate readings are erratic. SOS, I miss my balanced tank!

Tank specs: I have a low tech planted 15 gallon fluval tank, big sponge filter in the back (separated by a plastic panel from the main tank), light on 30% of the max it can go for 8 hours. Tank occupants are a handful of cherry shrimp, and an accidental ramshorn snail explosion that I'm in the process of getting under control (via assassin snail, acquired today).

Current parameters: Nitrate*: 40ppm; Nitrite: 0ppm; GH: 300ppm; KH*: 60ppm; pH*: ~6.8-7; Chlorine: 0

*=more on these below

I've got a few things going on that have crept up very slowly, so it took me a bit to realize that multiple parameters were shifting, and now I'm struggling to figure out which troubleshooting to do first, and how long to wait in between changes. 

The full story:

When I first got my cherry shrimp, I had lots of algae and bio-film built up for them (I cycled for ~4 months with plants: java ferns, christmas moss on driftwood, one bacopa carolina) and a nicely balanced tank--my Easy Green fertilizer schedule was worked out and I wasn't having to do any water changes, just top-offs. Once they ate all the algae, I started feeding them a rotation of hikari shrimp cuisine/repashy/bug bites a couple times a week. I also got a fast growing floating stem plant (not waterweed but looks sort of like it?), a smattering of duckweed, and a hidden snail along with the shrimp.

Things seemed pretty good for a few months, except my java ferns started dying off...then the christmas moss....and the duckweed and floating stem plant grew rapidly. My fertilizer schedule became very unbalanced as I was trying to figure out how much and how often and testing nitrates every day. My nitrates would read 0, I'd dose first up to 10-20 and they'd drop rapidly, so I started dosing twice a week. Then I'd test and they would read at ~40+ for literal weeks. Then a sudden drop again back to 0-10. Meanwhile the snails were doing their thing and multiplying while I tried to collect all the eggs before they hatched (an impossible task /cries/).

While I was focusing on my java ferns and moss dying, and the duckweed+stem plant+and snail explosion, I noticed that over the past couple months my KH and pH have been slowly shifting. Using the aquarium co-op test strips, I used to have a KH reading of ~80ppm and a pH of ~7.4-7.6.

When I tested today, my KH reads at ~60ppm and my pH ~6.8-7. And, after dosing easy green two and a half weeks ago, my nitrates are still at 40+. (All other parameter have staying the same--VERY hard chicago water at 300ppm GH; 0 nitrite; 0 ammonia; 0 chlorine).

I read somewhere that nitrates can "use up" KH/alkalinity, which can make the KH and pH both drop. Is that a #fact?

And, lastly, my shrimp have been disappearing over the past two months. I started with 8 shrimp about 7 months ago and now I can only find 2. They were molting fine, and grazing on the logs, hanging out all over the tank, one even laid eggs (that the snails ATE) but then fewer and fewer were visible. I thought at first they were hiding in the back of the tank, but I couldn't find them. I've only seen the same 2 shrimp for weeks. They seem relatively uninterested in the shrimp food (though the snails hustle to it), preferring to pick over the driftwood and the dying java ferns. I cut back on shrimp food to accommodate. Lastly-lastly, while the snails are multiplying quickly, there's also a scattering of empty snail shells across my gravel, of different sizes. 

Here's what I've come up with as a plan so far:

-I got an assassin snail today to try to get the ramshorn population under control. Maybe the ramshorns were outcompeting the shrimp for biofilm and other food?

-I'm going to do a 10% water change this week to try to get the nitrates back down, and see if it helps get my pH and KH back to where they used to be (80 KH and ~7.4-7.6 pH) and stabilized. From there, I'm not sure what to do....not fertilize for awhile just to let things settle?? I don't want to kill off new ferns and moss again when I don't fully know why they died in the first place.

-I ordered a phosphate test kit, a calcium test kit, and a potassium test kit after watching Irene's video on balancing a tank. Maybe I'm low on phosphate and/or potassium and the java ferns got sad? Maybe my calcium is low even though my GH is 300ppm? I had a very hard time identifying which nutrient deficiency the ferns were having since they were having lots of symptoms.

-I thought of clearing out some of the duckweed--maybe it blocked too much light for the christmas moss?--before I try to add new moss (I picked up some java moss today that I put in a five gallon tub with a dose of easy green up to 10-15ppm nitrates, nano pump+sponge filter, and just a cheap LED)

-I'm considering pulling out the fast growing stem plant entirely to try to "start over" with the plants. Would this shock my tank system too much? Should I cut it back week by week until it's gone? I'm worried it could be responsible for gobbling nutrients before my slow growers (fern, moss) could get it. But then why do my nitrates sit at the same level for weeks and weeks and then drop? I thought the shrimp would like it but I literally never see them on it. I do see the snails on it frequently--could they be eating all the biofilm first and so the shrimp aren't interested?

Are there any other things I should add to my plan, or things to definitely avoid? I feel a bit out of my depth handling so many seemingly disparate issues at once. And, any recommendations for shrimp food to try? I've got repashy community, hikari shrimp cuisine, and fluval bug bites for shrimp--my red cherries are totally uninterested in all three.

I'm sorry this is so long, but I wanted to give as much info as possible. I am truly grateful to anyone who makes it through and has any thoughts or advice!

--R

[BuzzDaddy21]

On 5/1/2022 at 2:25 AM, rnn said:

one even laid eggs

I`m sorry your having trouble. I`ve had a shrimp that dropped her eggs just before she passed other than that I watch them carry until they`re born. Shrimp are very good at hiding. I also have a ton of ramshorn snails in one tank because I over feed this tank. Do you have any fish stock? I will be no help about plants. I used to have lots of trouble with tanks, but I changed some things and tanks are doing great now. 

I know this didn`t help, but I know others will be better to help you. Good luck.

[Guppysnail]

On 5/1/2022 at 2:25 AM, rnn said:

one even laid eggs

Shrimp carry eggs until they hatch.  Some inexperienced new mother shrimp drop them accidentally, some drop them if they are infertile or the mother is I’ll or stressed.  Here is one of my first time moms dropping.  Just prior to hatching you can see the eyes when the mother is still carrying. 
here is a video of one of my first time moms accidentally dropping eggs. 

 

[rnn]

@BuzzDaddy21 thank you for your support! I don't have any fish stock, just the shrimp--I tried to be super careful about over feeding but that definitely could have happened when I was thinking I had more shrimp in hiding vs them being gone, so it could have contributed to my snail boom earlier on.  
 

@Guppysnail and @BuzzDaddy21 thank you for the extra shrimp info! My fault for being imprecise in an attempt to have a shorter post--I should have said she was berried, and that she dropped 7-8 eggs several weeks into carrying; only one of her berried eggs hatched as far as I could tell. The snails ate the dropped eggs before I could try to nab them. I'm not sure what happened with the rest of her berried ones, as shortly after I wasn't able to find her. Thank you for sharing that video, it's very helpful to see!