Remineralized RO vs Well Water PH/GH/KH/TDS

[jalbright]

I'm trying to wrap my head around the numbers I'm seeing and really understand what I should be looking at in terms of hardness and PH overall.  We have a few small tanks and started with neocaridina shrimp.  Because we already had an RO system and everything I read recommended remineralizing RO water, we've been using RO with Salty Shrimp GH/KH+.  Now that we have more tanks going and are about to add another, it's becoming a bit of a bother to mix the RO water in 5 gallon buckets.  This inspired me to test my well water and see what it looked like and if it would make sense to use it in at least some of our tanks.  So here are the numbers...

 

RO w/SS (4g/5gal):  TDS 144, PH 7.4, GH 8, KH 3

Well Water............. :  TDS 140, PH 7.6, GH 15, KH 11

 

I'm confused by how the TDS can be so similar and the GH/KH so much higher in the well water.  Is there a lot of something other than calcium, magnesium, and carbonates/bicarbonates in the SS?  I'm also not sure which measures are more important when considering what livestock would be appropriate for the parameters.  The new tank will be a community tank with fish, shrimp, and snails so I want to get a handle on this before deciding on inhabitants.  Thanks!

 

[jayc]

3 hours ago, jalbright said:

I'm confused by how the TDS can be so similar and the GH/KH so much higher in the well water.  Is there a lot of something other than calcium, magnesium, and carbonates/bicarbonates in the SS?

The opposite actually. SS GH/KH will have enough calcium and magnesium for shrimps, the rest of it is made up of other minerals that don't register on GH & KH tests.

TDS measures the total dissolved solids, ie. any dissolved minerals in the water.

GH primarily measures calcium and magnesium in the water (plus some other ions to a smaller extent).

KH measure the carbontes & bicarbonates in the water.

 

So your well water has a TDS of 140, which is high in Calcium or Magnesium (more likely calcium as that is more abundant in the ground) giving it a high value in GH of 15 (that's too high for shrimps by the way). Clay in soils for example is high in Calcium.

And it is high in Carbonates KH resulting in a higher pH, which makes sense since this ground water has filtered through rocks and sand, and has collected the carbonates/bicards in the water as it flows through it.

 

On the other hand RO water mixed with SS GH/KH+ is made up of the right amount of calcium and magnesium giving it a lower value of 8 and more ideal parameter for Neo shrimps. It also doesn't have as much carbonates/bicarbs, only a little which Neo shrimps like. This lower KH value gives it a lower pH value. Which will drop even more once it is in a cycled matured tank.

This SS RO water has a similar TDS of 144 because the Calcium and Magnesium used consists of extra minerals that does not affect the shrimp, and does not register on GH or KH tests. BUT it is picked up by a TDS meter. As an example, the calcium used in the production of SS GH/KH+ is Calcium Chloride or Calcium Sulphate. The GH test kit can pick up the Calcium ions, but it does not measure the Chloride or Sulphate ions. But the TDS meter will pick up traces of both Calcium and Chloride (or Sulphate depending on what the manufacturer used). Likewise, the magnesium used will be in a form of Magnesium Sulphate. Again the sulphates are only picked up by the TDS meter.

The well water in this case is not suitable for use as is. It needs to be mixed with RO to bring down GH and KH.

 

Hope that helps.

Edited June 18, 2020 by jayc

[jalbright]

52 minutes ago, jayc said:

Hope that helps.

That helps a lot and makes perfect sense, thank you!

 

Would there be any downside to cutting well water with RO to get something like GH 7-8, KH 5-6 and TDS 70ish?  For Neos is that TDS too low, KH too high?

 

When talking about fish that like softer water (tetra and rasbora for example), is that referring  to lower PH, GH and TDS or more one area than another?  I feel like from what I've read, people say soft water but talk mostly about the PH as a measure.  But then I also feel like I have read more than once not to worry too much about PH and to focus on GH/KH/TDS.

[jayc]

22 hours ago, jalbright said:

Would there be any downside to cutting well water with RO to get something like GH 7-8, KH 5-6 and TDS 70ish?  For Neos is that TDS too low, KH too high?

Is that a 50:50 mix to get GH 7-8, KH 5-6 and TDS 70ish? Looks like you need more RO water to reduce the KH and GH a bit more.

Add more RO to get it down to GH5-6 and KH 3-4. Measure how much RO and well water is used to reach those figures. 

TDS will be lower once you hit those figures. It will need a boost with Calcium Sulphate. 

It's a lot more work than necessary. You should just stick to RO water 100% and remineralise with Salty Shrimp.

Looks like the downside is mixing the right ratio of well water to RO water to get the right parameters is going to be too tedious.

There is no benefit to using the well water. Your well water is perfect for African cichlids however. That, and Sulawesi shrimp. Can you get Sulawesi shrimp where you are?

Edited June 19, 2020 by jayc

[jayc]

5 hours ago, jalbright said:

When talking about fish that like softer water (tetra and rasbora for example), is that referring  to lower PH, GH and TDS or more one area than another?  I feel like from what I've read, people say soft water but talk mostly about the PH as a measure.  But then I also feel like I have read more than once not to worry too much about PH and to focus on GH/KH/TDS.

The parameters like GH, KH, pH and TDS are all interlinked. Afterall, we are talking about water. Those are just measurements of certain elements that are IN the water. They are all measurements of a certain parameter that make up the whole chemistry of water. 

pH is a measure of how much Hydrogen (H) is in the water ("H"20) - the more H is in the water the more acidic it is. Conversely, the less H in the water the more alkaline it is. 

GH - as mentioned, is a measure of Calcium and Magnesium (mostly), the test kit does get influenced by other minerals.

KH - as mentioned is a measure of Carbonates and Bicarbonates.

TDS - is a measure of Total dissolve solids. That is, a measure of everything else that is soluble in water. But it does not tell you what is in the water specifically. That's why we never rely on just one measurement. You can't rely on just TDS. Likewise you can't rely on just pH. It doesn't tell you the whole story. 

So when you are talking about softwater, it means a low measurement of ALL those parameters. You cannot have a high pH but low KH. Or a high TDS and still expect a low GH. When you have a low TDS, it generally means you have low Calcium & magnesium (measured with GH kit), low Carbonates (measured with a KH kit). And because KH is low, pH will hence be low as well.

When people talk about one parameter like pH only, it either means that they emphasise it too much and don't understand the relationship with other parameters, or they don't have any other test kit apart from a pH meter/test kit. Either walk away, or you can try educating them. If you rely on just pH as an indicator of softwater, you might still fail to provide a softwater fish with the right environment. It might be right, as that is one parameter we measure to indicate "softwater". But what if you have a low pH, GH and KH but TDS is super high like in the 400's? It means that the water is full of another chemical or mineral or dissolved metal that your test kits are not picking up. If pH is only one part of the story, than knowing the other parameters means you have a much clearer picture of the story.

Those are only the 4 most common test we do in our hobby. That are many, many other tests that measures ONE specific parameter in water. You already know about the 4 mentioned above, we also commonly measure nitrogen ( ammonia, nitrite, nitrates), we have test kits for just Calcium, for just Magnesium, there are test kits for Oxygen, Iron, .... the list goes on.

So when we say "softwater", what do we mean specifically? That is the question. 

For a tetra or dwarf cichlid that comes out of the Amazon river? Those are from softwater, yes, but Blackwater more specifically. The tannins and humic acids that make up the Amazonian blackwater is a big part of recreating the fish's environment. I guess what I'm trying to say here is that the term "softwater" is very generic. So if you need specifics, than you need to ask for specific parameters.

Edited June 19, 2020 by jayc

[sdlTBfanUK]

I can't add anything to JayC superb answer but would definitely back up you should stick with RO plus minerals water. Often it can work with tap water with cherry (neocaridina) shrimps, I do that, but your source water is waaay off and not even worth considering as even mixing will mean you still need the majority as RO water anyway. There is too much risk for too little (if any at all?) benefit!

Where are you based that has this hard ground water?

Welcome to the forum by the way, hope you enjoy it.

Simon

Edited June 19, 2020 by sdlTBfanUK

[jalbright]

Thanks for the detailed responses and all the info, I really appreciate it.

 

I'm in the US, central Wisconsin.  My well water isn't even all that hard for the region, but it's enough to be a mess.  I have the house on a softener and then run that through the ro for drinking, but I have a tap in the basement if I want it straight from the well.

 

I am familiar with the Cardinal Sulawesi shrimp and they can be had in the US, but they range from $15-$25 each.  I'm not nearly confident enough in my ability to keep them alive to buy anything that expensive yet.  Maybe someday, they are beautiful and I'd be lying if I said I haven't thought about it.