[Rosalaine]

From my understanding of TDS it's impacted by pretty much everything in the aquarium, but it leaves me in a position where I don't really know if my aquarium is suitable for the shrimp I want to keep, or how to get it where it needs to be if it's not.

My aquarium is cycled, no issues with spikes, and for the most part my PH/GH/KH all read around where I want them to in the aquarium, but my TDS is always far higher than the range I've read for caridina. Outside of the aquarium, my distilled water reads at 0 TDS, and when re-mineralized to the PH/GH/KH I want the TDS is spot on as well, so I think my meter is at least relatively accurate. The aquarium does have a lot of plants, which went through an initial period of acclimation (they were a bit rough from shipping, some weren't very healthy, some had a bit of melt, etc) which I figured almost certainly raises the TDS since it's organic matter breaking down. Everything is looking healthy and growing well now. The aquarium has fluval stratum, okho stone, and driftwood (spider and cholla). The TDS right now is at 247 after a small water change last night and I feel like it barely drops after a water change.

My shrimp are doing fine, but there's no breeding. I'm pretty certain at least two of the tigers are male, though I wouldn't be surprised if three of them, or even all four, are male. My amano ladies aren't currently berried, but they were berried before the rescape and dropped their eggs as a result so based on when they've berried in the past I wouldn't expect them to be berried again yet.

In short, how important is the TDS for caridina, particularly if the other parameters are right and the water is distilled/RODI and reading pure before remineralization? I'd really like to add more shrimp in the near future, but with the TDS being so high I'm afraid it'll hurt them or they'll fail to thrive. Will I be able to lower it with regular water changes, or is it just a side effect of having a planted tank and not something to worry about? Sorry for all the questions.

 

[Zoidburg]

What parameters are you remineralizing to?

As your TDS meter calibrated?

 

[Rosalaine]

What parameters are you remineralizing to?

As your TDS meter calibrated?

Sorry for the delay, I went to prepare a gallon of distilled water just to give you the most accurate response.
The distilled water is sitting at 0 TDS, 0-1 GH, and 6 or less PH.

Remineralized (SaltyShrimp GH+), I get the following:

TDS: 100
PH: ~6.2
GH: 5-6

The PH is a deep yellow at this parameter but not quite tinted green like 6.4, definitely darker than 6.0 though. I'd like it to be closer to 6.4, but that puts the GH up to 7-8.

I haven't calibrated the meter myself, it was pre-calibrated. I have two of them, the same type and they're consistent with each other within 1-3 TDS.

 

[SardinePatheNews]

mine sits at low 300s , I think of tds as more an indicator of stability, if gh/kh/tds/nitrate are all steady i figure im in a good place and my shrimp seem to agree.
One thing i would advise (you may already do it but it wasn't mentioned) is top up the tank with the RO/distilled before measuring and water changing to avoid mineral ppm creep from any evaporated pure water being replaced with remineralized water.

edit: kh6 gh8 nitrate 0 are the other numbers in my shrimp tank and my change water is 180ish (3:1 mix of RO and finest tap water)

 

[Zoidburg]

That sounds all good. Is the GH higher in the tank at all?

 

[Rosalaine]

mine sits at low 300s , I think of tds as more an indicator of stability, if gh/kh/tds/nitrate are all steady i figure im in a good place and my shrimp seem to agree.
One thing i would advise (you may already do it but it wasn't mentioned) is top up the tank with the RO/distilled before measuring and water changing to avoid mineral ppm creep from any evaporated pure water being replaced with remineralized water.

edit: kh6 gh8 nitrate 0 are the other numbers in my shrimp tank and my change water is 180ish (3:1 mix of RO and finest tap water)

What kinds of shrimp are you keeping? I have blue tigers in there right now, but I'm hopeful of eventually having a mixed caridina tank and it feels like I'll never have my parameters suitable.
I do top up with pure distilled water, I have an open top so there's a lot of evaporation.

That sounds all good. Is the GH higher in the tank at all?

I think it's a bit higher currently, 7-8 maybe? I'll double check it after I finish dinner and update here if I'm wrong.

 

[SardinePatheNews]

sorry i should have said, mine are neos and the kh leveling effect of my substrate is long gone so my water is going to be bit harder hence being be about 70 tds above yours but if you have the key params spot on there is not much you can do to avoid a bit of tds pollution from botanicals and decor short of using a bare glass box so providing those key params are good I view the tds as a stability barometer rather than something to chase a specific value of that isn't natural to my tank.

 

[en7jos]

Hi @Rosalaine,

Work out your total dGH + dKH then multiply by 18 to get the respective TDS (ppm). So you said about 8 dGH in the tank so if the KH is 0 then (8+0) x 18 = 144 ppm. So you know that 144ppm of your TDS is GH and KH and the rest (about 100ppm) is something else. Prevailing wisdom seems to be that caradina shrimp like "clean" water, i.e. a TDS that is not too much above the GH+KH ppm total, which would suggest that your tank water has a "high" TDS. I can't say whether or not these recommendations are correct or not for your shrimp as I've not (yet!) kept them myself. But if everything else seems spot on and they aren't quite thriving as you would like then maybe reducing the TDS is something to consider?

Before you do though, buy some calibration fluid and calibrate your TDS meters. Don't rely on the factory calibration which can be off. Reading 0ppm for distilled water is also not an indication of accuracy of readings higher up. I wouldn't do anything until you are sure sure that your tank TDS readings are correct. (From what you described, they don't seem a million miles off though given the TDS of your remineralised distilled water).

Lowering TDS in a shrimp tank is hard because big water changes are a shock for the shrimp. So a couple of suggestions:

1) add a bag of Purigen to the filter and see if this brings down the TDS.

2) take out a small amount of tank water at a time a replace with distilled water. Repeat multiple times over the course of a week to bring slowly down the TDS (keeping an eye on your GH and stopping when it gets to your preferred level).

3) Try this:

But do make sure you are completely confident in your TDS readings before doing anything (i.e. buy some calibration solution for $9):
https://www.amazon.com/gp/product/B001VE99X8

Regards, James =]

 

[Rosalaine]

Hi @Rosalaine,

Work out your total dGH + dKH then multiply by 18 to get the respective TDS (ppm). So you said about 8 dGH in the tank so if the KH is 0 then (8+0) x 18 = 144 ppm. So you know that 144ppm of your TDS is GH and KH and the rest (about 100ppm) is something else. Prevailing wisdom seems to be that caradina shrimp like "clean" water, i.e. a TDS that is not too much above the GH+KH ppm total, which would suggest that your tank water has a "high" TDS. I can't say whether or not these recommendations are correct or not for your shrimp as I've not (yet!) kept them myself. But if everything else seems spot on and they aren't quite thriving as you would like then maybe reducing the TDS is something to consider?

Before you do though, buy some calibration fluid and calibrate your TDS meters. Don't rely on the factory calibration which can be off. Reading 0ppm for distilled water is also not an indication of accuracy of readings higher up. I wouldn't do anything until you are sure sure that your tank TDS readings are correct. (From what you described, they don't seem a million miles off though given the TDS of your remineralised distilled water).

Lowering TDS in a shrimp tank is hard because big water changes are a shock for the shrimp. So a couple of suggestions:

1) add a bag of Purigen to the filter and see if this brings down the TDS.

2) take out a small amount of tank water at a time a replace with distilled water. Repeat multiple times over the course of a week to bring slowly down the TDS (keeping an eye on your GH and stopping when it gets to your preferred level).

3) Try this: https://www.youtube.com/watch?v=0hFw7zG70As&t=159s

But do make sure you are completely confident in your TDS readings before doing anything (i.e. buy some calibration solution for $9):
https://www.amazon.com/gp/product/B001VE99X8

Regards, James =]

Thank you! I purchased that fluid, it should be here tomorrow so I'll see how to calibrate my meter and try that out. I bought some purigen as well, which will be here saturday, so hopefully by next week I'll be on the right path for keeping caridina. I figure even if my TDS meter ends up being in purigen could be beneficial.

I used my RODI today and found that has a slightly higher PH than the distilled - 6.4-6.6 for the RODI as opposed to the <6.0 for the distilled. I'll likely start using that to bump the PH a bit. It reads with 0 TDS as well.

Did a water change today, following a 3 day treatment of No Planaria for hydra (all gone it looks like!) and after capping up the evaporated water and adding about half a gallon of new water my GH is sitting at 6 and PH at ~6.0 still. My TDS according to the meter is 205, and I'll test again and update with the results of the recalibrated test once the fluid gets here and proceed from there.

Thank you to everyone who's offered me advice on my shrimp journey, I don't know anyone in person who keeps shrimp (or even aquariums) and while I do have a really good, private LFS in my area I haven't been able to go there since the pandemic.

 

[en7jos]

Great, let us know how you get on!

I used my RODI today and found that has a slightly higher PH than the distilled - 6.4-6.6 for the RODI as opposed to the <6.0 for the distilled. I'll likely start using that to bump the PH a bit. It reads with 0 TDS as well.

Note that pH readings of distilled and RO water and pretty much meaningless as there is no buffering (KH). Both distilled and RO are pretty much a blank slate with regards to Ph; without any KH the pH can very easily be affected by the additional of anything into the water. As soon as either water hits your tank, has anything added (e.g. minerals), then the pH will change accordingly.

Happy shrimp keeping! =]

 

[Rosalaine]

Great, let us know how you get on!



Note that pH readings of distilled and RO water and pretty much meaningless as there is no buffering (KH). Both distilled and RO are pretty much a blank slate with regards to Ph; without any KH the pH can very easily be affected by the additional of anything into the water. As soon as either water hits your tank, has anything added (e.g. minerals), then the pH will change accordingly.

Happy shrimp keeping! =]

Both the calibration fluid and the purigen have been delivered! So I'm going to see about calibrating my tds meter asap.

Do you have any recommendation for gently bumping the PH of my aquarium? The SaltyShrimp GH+ doesn't seem to alter it at all, and my aquarium itself is at 6.0 or lower currently. I'd like to get it to 6.2-6.4 so I could monitor it's stability a bit better. I'm using fluval stratum for substrate, and from my understanding using anything with KH will start to exhaust the substrate.

Update: With the calibration fluid you linked my TDS meter reads 365, so about 23 ppm more than the fluid indicates it should. I have two of the same type, the other reads 354, so closer at 12 ppm more than the fluid indicates. These meters don't seem like they can be recalibrated, however, so I'm going to shop around for one that can be.

 

[ahem]

Hi @Rosalaine,
Before you do though, buy some calibration fluid and calibrate your TDS meters. Don't rely on the factory calibration which can be off. Reading 0ppm for distilled water is also not an indication of accuracy of readings higher up. I wouldn't do anything until you are sure sure that your tank TDS readings are correct. (From what you described, they don't seem a million miles off though given the TDS of your remineralised distilled water).

Thank you for this advice. I did not realize such a product existed and just ordered. I bought a cheap TDS meter and was using it more for a "ballpark figure" assuming it wasn't that accurate. I've been relying more on my GH and KH API drop tests with the TDS meter as a sanity check on top of that. The calibration solution will let me know if my $20 meter is any good! You can't really go cheap on a pH meter as cheap pH meters tend to be inaccurate, some wildly so. I'm hoping that with TDS you can go cheap, we'll see.

 

[Zoidburg]

The TDS meters should be calibrated using a tiny little screw in the back. There should be a hole where you can insert said tiny screwdriver to change the readings.

No hole, not likely able to calibrate.

 

[Rosalaine]

The TDS meters should be calibrated using a tiny little screw in the back. There should be a hole where you can insert said tiny screwdriver to change the readings.

No hole, not likely able to calibrate.

Yeah, unfortunately when I looked into it further reviews said it couldn't be calibrated (it was a cheap one, I bought it back before I ever intended to get into caridina and such) so I've ordered a well-reviewed adjustable one and it's due on sunday. This hobby is a total money pit for me but man I love those little guys

 

[en7jos]

The TDS meters should be calibrated using a tiny little screw in the back. There should be a hole where you can insert said tiny screwdriver to change the readings.

New HM Digital models are electronically calibrated via the buttons on the front; much simpler and more precise!

The calibration solution will let me know if my $20 meter is any good! You can't really go cheap on a pH meter as cheap pH meters tend to be inaccurate, some wildly so. I'm hoping that with TDS you can go cheap, we'll see.

My experience with cheap meters is that you might get lucky with a good one that is accurate, or it might be miles off. But even with the 'good' ones I'm not convinced about long term repeatability and consistency of the calibration. But once you have a pot of calibration fluid, you're sorted so long as you regularly check the reading is sensible!

Do you have any recommendation for gently bumping the PH of my aquarium? The SaltyShrimp GH+ doesn't seem to alter it at all, and my aquarium itself is at 6.0 or lower currently. I'd like to get it to 6.2-6.4 so I could monitor it's stability a bit better. I'm using fluval stratum for substrate, and from my understanding using anything with KH will start to exhaust the substrate.

Yes - one recommedation: wait! :grin2:

Adding a small amount of KH / buffering will temporarily raise the pH, until the soil absorbs it and the pH goes back down again. You can keep going like that until the buffering is exhausted, but then you have no buffering capacity left which kind of ruins the soil. With time the pH will naturally start to rise and should stablise at the levels you want. But adding KH will just cause the pH to fluctuate which is probably worse for the critters than a stable but slightly low pH would be. So my advice is to do nothing (except don't add too much drift wood, leaves, etc that might reduce the pH further).

Update: With the calibration fluid you linked my TDS meter reads 365, so about 23 ppm more than the fluid indicates it should. I have two of the same type, the other reads 354, so closer at 12 ppm more than the fluid indicates. These meters don't seem like they can be recalibrated, however, so I'm going to shop around for one that can be.

I thoroughly recommend this model:
https://www.amazon.com/HM-Digital-Dissolved-Resolution-Accuracy/dp/B007KDYOMU/

Works great, digital calibration with the buttons on the front (no faffing round with a small screwdriver), reliable, good quality. Cheaper TDS meters do not have temp compensation so, if you're bothered about accuracy (and I'm not sure how much this affects readings across typical aquarium temps), get one with temperature reading and compensation.

 

[Zoidburg]

I have the blue model TDS meter.... but I just might have to grab that fancy smancy one!


@Rosalaine I got into shrimp keeping because of someone else! As in... I had to buy stuff to figure out why THEIR shrimp were dying. I have now stupidly overstocked my tank with fish.... not that it's an issue atm... I need a bigger tank! lol

 

[Rosalaine]

With my new and calibrated TDS meter my caridina aquarium is at 218 ppm! Still higher than I want, but far better than my original readings with the other meter. I'm going to add the purigen and see if that brings it down. Fingers crossed that I'll have everything right soon!

Yes - one recommedation: wait! :grin2:
Adding a small amount of KH / buffering will temporarily raise the pH, until the soil absorbs it and the pH goes back down again. You can keep going like that until the buffering is exhausted, but then you have no buffering capacity left which kind of ruins the soil. With time the pH will naturally start to rise and should stablise at the levels you want. But adding KH will just cause the pH to fluctuate which is probably worse for the critters than a stable but slightly low pH would be. So my advice is to do nothing (except don't add too much drift wood, leaves, etc that might reduce the pH further).
I thoroughly recommend this model:
https://www.amazon.com/HM-Digital-Dissolved-Resolution-Accuracy/dp/B007KDYOMU/
Works great, digital calibration with the buttons on the front (no faffing round with a small screwdriver), reliable, good quality. Cheaper TDS meters do not have temp compensation so, if you're bothered about accuracy (and I'm not sure how much this affects readings across typical aquarium temps), get one with temperature reading and compensation.

I didn't know that about pH! Thank you, I'm glad it's not something to be too concerned about right now. I figured it'd stay roughly where it was and I'd always have < 6.0 if I didn't find a way to bump it. I'm still new to remineralizing water, my tap parameters are suitable for neos but I don't really trust it not to have something toxic in it that'd murder my little guys, so I invested in a RODI when I decided to get shrimp.

That's the tds meter I ordered actually, it was "frequently bought" with the calibration fluid you linked. Glad to hear a firsthand opinion of it! It should be here tomorrow and I'm really excited for it haha.

I have the blue model TDS meter.... but I just might have to grab that fancy smancy one!
@Rosalaine I got into shrimp keeping because of someone else! As in... I had to buy stuff to figure out why THEIR shrimp were dying. I have now stupidly overstocked my tank with fish.... not that it's an issue atm... I need a bigger tank! lol

Oh no, a bigger tank? That sounds horrible... I tried keeping shrimp once several years ago, had some low grade cherries from a LFS, they lived and did pretty well but never bred. One or two of the females were berried when I got them and the eggs hatched and the fry grew up without issue. Females were saddled but never berried. I didn't really know about parameters and tds then, so that was probably part of it.

 

[Rosalaine]

Did a small water change today! My TDS is sitting at 188 following the water change and my GH is at 6. My PH is still bright yellow (pic below), but I'm not going to stress about that for now. Right now my focus is just gradually trying to bring down my TDS. The OEBT are looking particularly vibrant these days.

10/18: After another water change we're at 155 TDS, 5 GH, and 6 PH. We're getting there.

10/21: 137 TDS, 5 GH, 6 PH (Bought a wide-range PH test scaling 5-9, it's pretty much exactly at 6 it seems)