TDS

[Tinyfellows]

I recently bought a tds meter and am currently trying to understand where the difference in my tap water and tank water came from. Out of my tap my tds is around 160 with a dkh of 0. Then when I check the tds in my nano shrimp tank the tds was 360.
 

I have crushed coral in my substrate that puts my tank dkh ph 4. My dgh in the tank is 16 did my general hardness get so high from topping off with tap water?

And would it be safe to use Rodi water to bring the general hardness down to lower my tds? If I did do this would my kh stay around the same level since the coral is in the substrate? 

[Fish Folk]

If all you do is top off, then it's possible that your larger molecules just stay in the aquarium and do not evaporate. Out of curiosity: do you find that there is any discrepancy when measuring pH between your tap and your tank?

If you want to really lower TDS, yes, using gRODI water after a normal water change can produce that. However, realize that the life in your tank -- your plants, shrimp, etc -- have grown accustomed to these parameters. If things change too suddenly for them, they can suffer and die off. Because they naturally absorb minerals, one way to lower hardness is to include a lot of plant life.

[Tinyfellows]

My tank is heavily planted. I had to do just top offs for a couple months cause I cut my finger off in a work accident and couldn’t manage full water changes. If I brought it down I would lower it over time so it wouldn’t shock the shrimps systems. All the shrimp seem to be doing fine I just don’t want them to start having molting issues with the high tds 

[Andy's Fish Den]

A lot of dissolved mineral and other stuff in the water doesn't evaporate, the TDS will creep up. It's like in a saltwater tank, you only top off with RO/DI water because the salt doesn't evaporate. 

You could slowly do  water changes with RO water to help bring the TDS down. 

[David W]

The crushed coral in your substrate will add minerals to the water increasing the TDS. That is the purpose of using crushed coral, adding minerals to make hard water fish happy. 

Please keep in mind TDS just measures how much "stuff" is dissolved in your water, but not what stuff.  TDS meters don't distinguish between Iron, Calcium, Arsenic etc...

If your PH is stable and you have a regular maintenance routine it should all work out. Stability is usually more important than chasing a number. 

    

[tolstoy21]

I'd measure the known parameters like Ph, Kh, GH, Nitrates, etc. and not worry about the TDS numbers.

i find TDS useful only in very specific circumstances, like if you're remineralizing zero TDS water with a known mineral or additive and want to see how much you've mixed in. In that scenario you have complete understanding and control of the environment.  In a tank full of fish, all you know is . . . there's more 'stuff' dissolved into the water this week compared to last.

I find the basic measures that most kits measure for to be adequate enough to gain a general understanding if your water is Ok, needs changing, requires amendments, etc.

I find crushed coral doesn't move the Gh as much as the Kh. If your Gh is is increasing exponentially, and you don't have anything mineralizing it, this could be caused by evaporation and top off. 

If the Gh of your tap water is within the range you want it to be in, then just start to reset the Gh with water changes.

[tolstoy21]

@Tinyfellows What kind of shrimp are you keeping in your nano tank? if they are breeding and you have baby shrimp growing up in there fine and healthy, then I would day, just make sure your parameters don't run away on you.

I would suspect Gh is the main culprit driving your TDS up, if your Gh is rising but your Kh has remained steady, but that's just a guess.

If your tap water has zero Kh, then a water change could lower your Ph a little temporarily (unless you did a single gigantic water change).

Unless you keep a really fragile shrimp species, I'm sure they will be fine with partial water changes.

I'd start with your tap water and see if that achieves your goals before investing in an RO setup.

 

Edited August 25, 2021 by tolstoy21

[Tinyfellows]

@tolstoy21 I just have red rilis in the tank. I stocked the tank 2 months ago with 10 and one came home berried and those have hatched and grown up. I have many femal a with saddles currently but none have become berried yet 

[tolstoy21]

On 8/25/2021 at 2:30 PM, Tinyfellows said:

@tolstoy21 I just have red rilis in the tank. I stocked the tank 2 months ago with 10 and one came home berried and those have hatched and grown up. I have many femal a with saddles currently but none have become berried yet 

My orange rilis do Ok in 8 dGH, which is the hardness of my well water. My Kh is 0 (or maybe it's 0.5, either way, it's low) and they are doing AOK.

Like I said, I'd just compare the GH of your tap water to the current tank, and then decide if it's in your best interest to try to lower the GH. But if you're shrimp get berried and have young ones, then just leave things are they are.

Or experiment a little bit. Unless you make drastic changes, your shrimp should be fine (unless they go belly up, and in that case, I never posted any of this!)

Honestly, the only way to learn this stuff and feel confidence is through some trial and error. 

Edited August 25, 2021 by tolstoy21