# 50% weekly water change is killing my shrimp?



## Neil6 (21 Feb 2021)

EI fertilizering for a 200lr heavily planted tank. Rules state do at least a 50%water change weekly but each time I do this I kill a few more 🦐 shrimp. Mostly cherry shrimps but today a few Amano too. Temperature of the water is good and it's RO water so no problems with chorine/ copper. 
By the end of the week the TDS is heigh 300-400 hence the RO water  being used to bring it down. Is the shock difference of the TDS killing off my shrimps? 
Most shrimp keepers say don't do 50% water change so what do I do?


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## Iain Sutherland (21 Feb 2021)

Is the RO remineralised?  If its straight RO then the tank is likely low on minerals essential to shrimp.
If your tds climbs so much it cant be controlled by normal weekly water changes then you need to reduce your fert dosing as the plants arent using enough .👍


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## Iain Sutherland (21 Feb 2021)

And before @ceg4048  gets here... there are no rules 🤪


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## Neil6 (21 Feb 2021)

That makes sense. So I need to slowly reduce my ferts till my TDS balances out over the whole week? Around the 150? TDS does reduce with the water changes but climbs again over the week. Using the recommendation for EI fertilizer- plants not growing enough yet? 
Shrimp die almost within an hour after water changes. Can the lack of minerals in the RO water do this. I suppose the difference between the two does it? 🧐


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## Neil6 (21 Feb 2021)

Neil6 said:


> That makes sense. So I need to slowly reduce my ferts till my TDS balances out over the whole week? Around the 150? TDS does reduce with the water changes but climbs again over the week. Using the recommendation for EI fertilizer- plants not growing enough yet?
> Shrimp die almost within an hour after water changes. Can the lack of minerals in the RO water do this. I suppose the difference between the two does it? 🧐


After water change TDS is '101'


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## Hufsa (21 Feb 2021)

Keep in mind that your Neocaridina (Cherry) shrimp will want a certain amount of GH in the water, I see many others have found around 6 degrees GH to be a pretty good spot. So you dont want your TDS to be too low either. But given that amanos have died right after waterchange, im leaning more towards shock. Amanos are quite hard to kill


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## Iain Sutherland (21 Feb 2021)

Tds climb is normal but if you base is 150, if you add say 500 tds (arbitrary) of ferts over the week it should still remain below 200 by the end of the week. 1 rest day and 50% wc should then reset it to your base at 150...
It's not always that simple though, my shrimp tank for example bases at 180 and I have to WC at 100 to maintain that as pollution is pretty high and I dose a lot of mineral feeds over the week. 
Ultimately if your tds rises lots during the week as you dose start pulling your ferts back a bit as the plants just arent using it or give it a mid week rest day etc...


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## Iain Sutherland (21 Feb 2021)

Also as shrimp die quickly after WC, is the RO water your own? Some shop have terrible R0 tds 80 etc which firstly is a waste of money but will also likely need dosing with something like seachem prime...


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## John q (21 Feb 2021)

Hufsa said:


> Im leaning more towards shock



I know nothing about shrimp but surely an instant tds change from 400 to 100 can't be good for them?


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## Hufsa (21 Feb 2021)

It almost has to be something quite significant to kill off several amanos within a few hours


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## Fred Dulley (22 Feb 2021)

You could keep doing the 50% water changes per week but pump/siphon the new water into the tank over a few hours rather than dumping in. I know that a few shrimp “experts” do this.


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## Wookii (22 Feb 2021)

If you are doing water changes with pure RO, you shouldn't be seeing TDS anywhere near 400-500, even from very generous fert levels. What is the TDS of your RO water?

It might be worth posting a full tank shot also, but do you have any sources of Calcium Carbonate such as Seiryu stone in the tank?


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## Kalum (22 Feb 2021)

i've only tried to keep amanos once so far and they lasted around 3 months before all 4 had passed, have kept cherries for a few years now and have done fine with 70% water changes 1-2 times a week but i also do occasionally see a couple which appear to be 'dead' during or after water change, i've also went back to remove them say an hour later and they are up and grazing again

As @Wookii mentions there is something not quite right if your TDS is rising to those levels in a week, there is something that is being added well in excess (ferts or.....?) or something leaching from within (such as calcium from rocks or tannins from wood). i'm lucky to have extremely good tap water around 40ppm TDS and reset to around 120 TDS after a w/c with it raising to around 180 in a week of EI dosing (currently it rises to around 220 due to very low plant mass as i'm waiting on plants like others so there is excess nutrients not being used)

If the shrimp are new to you then yes you will no doubt get a few casualties as they adapt to your water and regime, but once you have had them breed a couple of times they soon become bullet proof to most setups. consistency is key for ideal scenarios but keeping tds within a range of 100 is more than acceptable for most inhabitants


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## Nick potts (22 Feb 2021)

I find amanos pretty much indestructible, I have had a situation where have had to move a few amanos from 120 TDS water to a tank with 380+ TDS without acclimatisation and they have been fine. Of course not recommended.

You don't mention what hardscape you have, in a rock dominated tank TDS can rise quite a lot due to the rock leaching minerals.


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## Furgan (22 Feb 2021)

How are you changing the water? If it’s added too fast then the change in parameters could shock and kill the shrimp, also temp? I keep shrimp and when I change there water (60l tank) I drip the water back in so there isn’t any sudden changes.


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## Neil6 (23 Feb 2021)

John q said:


> I know nothing about shrimp but surely an instant tds change from 400 to 100 can't be good for them?


Yeah. Obvious to me now


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## John q (23 Feb 2021)

Neil6 said:


> Yeah. Obvious to me now


Can you not split your water changes, say 2 30% instead of 1 50% until you suss out the high tds problem?


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## Neil6 (23 Feb 2021)

Recording and keeping an eye on the TDS levels daily. Already reduced the micro and macro's slightly so see what that does.


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## Neil6 (26 Feb 2021)

Neil6 said:


> Recording and keeping an eye on the TDS levels daily. Already reduced the micro and macro's slightly so see what that does.


So I've been monitoring the TDS over a few days 
Monday=134
Tuesday=146
Wednesday= 158
Thursday= 168
Friday= 179
It's climbing a lots less than was beforehand.
Do I knock back the macro / micro ferts a little more? What is the optimal TDS for the plants /shrimp? Do I need a 50%weekly water change tomorrow?


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## Nick potts (27 Feb 2021)

Neil6 said:


> So I've been monitoring the TDS over a few days
> Monday=134
> Tuesday=146
> Wednesday= 158
> ...


Cherry shrimp are fine at those numbers, most would say 200-250tds for cherries but I know many on here keep them in tanks with full EI dosing and lots of rock so there TDS would be very high.

It's more the sudden change in TDS and other water parameters that can cause harm. 

I remineralise my RO water to around 120 TDS in my planted tanks and 180 in my dedicated cherry tanks


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## Neil6 (27 Feb 2021)

So what's the idea with the TDS? I am assuming the correct method is to remineralise the RO water to achieve your targeted TDS. Add daily EI fertilizer but only by the amount your plants are up-taking. So the TDS stays the same and doesn't climb?


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## dw1305 (27 Feb 2021)

Hi all,


Neil6 said:


> So what's the idea with the TDS? I am assuming the correct method is to remineralise the RO water to achieve your targeted TDS. Add daily EI fertilizer but only by the amount your plants are up-taking. So the TDS stays the same and doesn't climb?


That is how some of us <"run our tanks low tech">. I use a conductivity datum range together with the <"Duckweed Index">.

I still haven't written a proper article for the "Duckweed Index", but the <"linked thread"> gives some of the background.

cheers Darrel


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## Nick potts (27 Feb 2021)

Neil6 said:


> So what's the idea with the TDS? I am assuming the correct method is to remineralise the RO water to achieve your targeted TDS. Add daily EI fertilizer but only by the amount your plants are up-taking. So the TDS stays the same and doesn't climb?



Unless this is a dedicated shrimp tank I would not worry too much about TDS

The whole concept of EI fertilisation is overdose on the ferts, to ensure there is always excess available for plants to use. Of course, full EI is not the only regime and you can tweak it to suit what you want.


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## Ash_bash (20 Mar 2021)

I had this issue, the shop i buy my RO water from said they were adding remineraliser for me, turns out they weren't and after afew water changes i lost my whole CRS colony, now i dose it myself with salty bee remineraliser.


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## jaypeecee (20 Mar 2021)

Ash_bash said:


> I had this issue, the shop i buy my RO water from said they were adding remineraliser for me, turns out they weren't and after afew water changes i lost my whole CRS colony, now i dose it myself with salty bee remineraliser.


Hi @Ash_bash 

I know from personal experience never to trust high-street aquarist suppliers with RO water. The moral of the story is to take your TDS meter with you when buying your RO water. Test the water there and then whilst the shop attendant nervously watches on.

JPC


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