Crashed cycle in shrimp tank ammonia won't budge

I built a 5 gallon, heavily planted, filter less shrimp tank and everything was going fine for 3-4 months. I'm not sure why but my cycle suddenly crashed 2 weeks ago. At first I thought that it would recover relatively quickly since it was only .5 ppm of ammonia and when I cycled the tank I made sure that the tank could process 3 ppm of ammonia in 24 hours without plants. I dosed prime daily and waited a couple of days but the ammonia stayed at .5 ppm so I decided to get a sponge filter. I took some mulm from my twenty gallon and slathered it on the sponge to give it a head start and waited a few more days all the while dosing prime daily. However, the ammonia still was at .5 ppm so I went out and bought some seachem stability to see if that would help. It's been 4 days and the ammonia has stubbornly remained at .5 ppm. Is this normal when recovering from a mini cycle or cycle crash?

 

One after another in different spots of the tank. With 4 different results

 

One after another in different spots of the tank. With 4 different results

As you already know, That just doesn't make any kind of sense. I am leaning more and more to faulty tests. I am sure you do but I will ask anyway. Are you running a filter on this tank? If you are and it is circulating the water, the pH should be the same no matter where it is taken from the tank. There may be a slight difference between water taken from the very top and that taken from right at the bottom or if you run the test just before lights on and again several hours later but even then it shouldn't be more than a very slight difference.

 

Yea the hob is still on the tank so water circulation shouldn't be an issue. This tank is just a mystery box now. Well at least ammonia is going down...maybe.

 

Figured out why ph readings are all over. Apparently my kh dropped from 4-5 to 0 in a week......

I'm going to go with water changes to bring the ph and kh back up. How much should I be changing a day to safely do this? Ph of tap is 7.6 to 7.8 and the tank is 6.4 to 6.6. thanks

 

Since this is a tank with shrimp in it I am going to call richiep I don't want to tell you one thing and we find it was the wrong thing and your shrimp suffer. I am very new at keeping shrimp so am just now getting comfortable at doing water normal changes.

 

Just read right through this thread and it got a bit confusing with everything going in the tank, even dosing prime every day can impact on shrimp as its a chemical and its altering the chemistry,
No doing 4 tests and having a variation in ph of 1.6 says your shrimp should be dead as they can't take any sudden fluctuations of .5 thats the cut off,
To have taken them from 4 different parts of the tank and being such a small tank tells me the tests are inaccurate, that sort of chemistry just dosnt happen in such a small tank,
First I'd stop putting anything in the tank and give the tank a chance to stabilise then you can start a process of elimination if there's still problems, your shrimp are still alive albeit not moving much now so you need a base to start off.
If your other tanks are running the same water id do a 70% change with tank water from another tank,this will not have the sudden impact of fresh water and will help to start to stabilise the little tank.
You said your kh dropped to zero may also have started a mini cycle but I dont think so,
If this dosnt make any sense to you ignore it and go with what you feel is right, some of my points may trigger something off to help you.

 

Thank you Richie. this one has had me scratching my head for a while now. None of it is making any kind of sense to me.

 

Thank you Richie. this one has had me scratching my head for a while now. None of it is making any kind of sense to me.

Its a hard one to get to grips with i must agree

 

I've stopped adding stuff a few days back. My tap here is on the hard side which means all my tanks are ph of 7.6 ish, gh 7, kh 3-4. The shrimp I'm keeping are zebra babaulti and their tolerance range is quite high in terms of ph which is probably why some have survived. I checked the ph test with my other tanks and they gave numbers that made sense. Im not quite sure what used up the kh in the tank. I tested the tank a week ago and the ph was fine. I'm trying to stabilize everything through water changes but I don't want the parameters to swing wildly. How much water change do you think I should be doing with tap? Thank you

 

You can do 80% if things were really bad but if you do two 50% two days apart would do good,
Just make sure the temperature is as close to your tank as possible and introduce slowly.
Have you checked your tap for ammonia
And am I right in thinking you have ro water

 

Tap is ammonia free. I do have ro but use it mainly for top offs. 50% water change dripped in won't shock the shrimp? Thanks

 

50% will be fine if you drip it allow for it to drip onto the heater if you have one in there,
Do it three days apart to give things time to settle in between.
You can also do what ever tests you can before each change

 

Got it thanks.

 

Something just crossed my mind you said you use ro water for top off is that in your 5g as well and if so how much

 

Something just crossed my mind you said you use ro water for top off is that in your 5g as well and if so how much

I only top off whatever is evaporated at the end of a week. It's usually 28 fl oz so .22 gallons for the 5g.

 

Is that with plane ro water

 

Yes 0 tds to.

 

OK so let me get this straight you don't do water changes you just top up with ro water once a week

 

I do water changes maybe every 2.5-3 weeks but only like 8% I wanna say

 

Over time your ro water can have an affect if you end up using more ro water than tap, this would drop you ph to ph7 your gh0 kh0 this could well account for what happened to you
It will also take out needed minerals that ro water doesn't have

 

Even as just top off? Aren't minerals generally left behind during evaporation? Hmmm I admit I never tested kh frequently but I monitor tds and other parameters every 2 weeks because this was my first no filter tank. Ph did tend to trend lower than my other tanks but the lowest I recorded was 7.4. tds was definitely lower but I chalked that up to the fact it was only shrimp so lower load

 

Minerals are left behind but need refreshing regular as this in itself causes shrimp problems.
I would seriously think of turning that tank into ro water and reminerilising with salty bee you will have far more control,or, if you stick with what you got then only use tap water, babalti will do good in both, this could very well have been the start of your problems then

 

Hmmm so kh depletion, followed by ph crash, then leading to bacteria crash, followed by ammonia. I think you might be right. Thanks.

 

Thank you Richie. I think you have gotten to the bottom of what is happening here.

 

Ok final update. Looks like almost everything is back on track. Only slight issue is slightly higher gh but I'll add a bit of ro to fix that. Thanks again everyone.

 

This is good news. Thank you for the update