[StLCopperhead]

If you'd post the KH, GH, and TDS of your tap you may not even need RO though. I don't use it in Neo only tanks, but I have soft neutral tap that they do well in. Also if you have source water that varies at different times of year, RO may be helpful even if your water is usually on point.

Thanks so much for your reply; it was very helpful!

My tap water (without ageing) is:

pH: over 8.4 (it went past what my API test could measure)
gH: 6
kH: 3
TDS: not sure yet; should hopefully know by tonight.

Here’s what’s weird, though: I aged some tap water and tested it, and the gH spiked to 10! How did that happen? kH went to 5. That confused me totally. The pH did drop to 7.6, though.

There have been so many weird variables and readings and that’s what made me think maybe RO or RO/DI would be the way to go.

In my planted 75, my stats have been pretty steady:

Ammonia: 0
Nitrites: 0
Nitrates: 5
pH: 7.2
GH: 8
KH: 2

You can see how the tap water is pretty different from my tank’s. I always have some issues w my shrimp following a water change; despite ageing the water, only changing no more than 5 gallons, and matching temp & dripping the new water in. So water changes are a constant source of stress for me & I’m hoping having some control over the fresh water might help?

 

[StLCopperhead]

Bottom line is as @Greggz mentioned: pH 7.6 and dKH 5 makes sense for expected CO2 levels after allowing for degassing. Now, as to why KH and GH are rising after a day or two of different tap testing points, I have no idea: it shouldn't. I'd suggest the following:

Retest, but make sure to measure the tap water that is being degassed, before degassing it, i.e.; run both tests on the same glass of tap water (and make sure the API kit hasn't expired). I'd also increase the sensitivity of the tests by using 5x the amount of sample water for the tests, then divide the resulting measurements by 5.

Yes, it’s the crazy gH spike that baffled me. I repeated the test twice (on the same aged water) just to be sure. It made me doubt all of my other readings, honestly, except my 75 gallon results are still stable.

But I’ll test it again, and your suggestion is a good one. I use the API liquid tests for all parameters, and they are all less than 2 months old, and not close to expiration.

But...even assuming my aged tap water isn’t too bad, it still seems to affect the shrimp. Why? I dunno. I’ll keep trying to figure it out, but it has made me really want to try using remineralized RO water to see if it helps at all.

I really appreciate everyone’s input and help! There are so many nuances to keeping these crazy critters—I feel like no matter how long I have them, I’ll always be learning something new (and that’s a big part of the fun for me!).

Bump: FWIW, I wasn’t able to get the TDS pen tonight as I had planned; my LFS stopped carrying them for some reason so I’ll have to wait for a delivery from Amazon. Could TDS maybe be the culprit?

And actually, while I’m on the subject...TDS is something I don’t fully understand. Total Dissolved Solids, yes, but that could be anything, right? So what exactly does a TDS in a tank represent? Is a high TDS always a bad thing? I would assume they’re higher in heavily planted tanks?

I’ll go down the Google rabbit hole on this, but the problem with the ‘net research for me, so far, is all of the wildly conflicting info when it comes to shrimp. I’ve lurked here long enough to trust you guys, so I appreciate you humoring my both my newbie ignorance & my enthusiasm! 😁

 

[StLCopperhead]

Thank you for all of that info! That clears a lot up. Does a high TDS in straight tap water mean that the water is “hard?”

And should I expect my heavily planted tank to have a higher TDS in general than one without plants (assuming the same stock levels)?

 

[StLCopperhead]

Okay, that was really helpful. Thank you muchly!