• You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up

Perplexed about extreme TDS readings

jaypeecee said:
Hi @MichaelJ

Looks like you're not alone with Eco Complete problems:

www.fishlore.com

Carib sea eco complete problems | Freshwater Substrates - Gravel, Sand Forum | 436267

I posted in cloudy water but I thought I would post here too to see if anyone else had the same issues I did or can offer insight. I redid my 29 gallon with carib sea eco complete (about 3-4" ) Same bio media in filter that has been going for years. No fish to start(switched to my other tank)...
www.fishlore.com www.fishlore.com

JPC
Click to expand...

Hi JPC,

I do not know the exact content of the ECO Complete substrate. I've added some screen shots of the text from the Red EcoComplete planted aquarium substrate bag that gives more details about what CaribSea claims is the contents. It was recommended to me back in the day. However, there is really nothing from what it says on the bags that suggest it is completely inert I suppose?

I never had issues (to my knowledge) with sick/dying fish or elevated nitrate or ammonia levels since using this substrate. That being said, I do suspect the gravel is playing into my super elevated TDS levels somehow - perhaps worsened in part due to my past use of the Acid buffers as pointed out in the this thread. I am having a cup full of the gravel from the tank sitting in a bucket of RO water for a couple of days and see what happens to the TDS. Of course, that experiment won't tell me anything if its interaction between my current tank water and the substrate.

Cheers,
Michael
 

Attachments

  • EcoCompletePlantedBack.jpg
    EcoCompletePlantedBack.jpg
    502.8 KB · Views: 136
  • EcoCompletePlantedFront.jpg
    EcoCompletePlantedFront.jpg
    779.5 KB · Views: 123
Hi @MichaelJ

The sequence of events/key facts appear to be:

MichaelJ said:
The TDS is about 2-3 ppm when pure and about 280 ppm after mineralization using Seachem Adic buffer, Alkaline and Equilibrium.
Click to expand...

And then:

MichaelJ said:
So the Seachem Alkaline Buffer I use to (raise) target the 6-7 KH range (for Ph buffering). However, since that raises the Ph of the RO water from 7 to around 8.5, I am adding the Acid Buffer to bring the Ph back down to the neutral range.
Click to expand...

And then:

MichaelJ said:
My TDS in both my heavily planted 40g tanks are in the 1500 ppm range...
Click to expand...

So, it is a combination of factors that has driven TDS so high. Last night, I was having some difficulty getting the full picture. Looking at the list of ingredients in Eco Complete, the manufacturers really have tried to pack everything in there. It contains mycorrhizal fungus and even strains of probiotics.

JPC
 
Hi JPC,

My most recent KH are 6-7 and GH 8-9. Although I am not hyper confident with these cheap drop-counting test kits, I do expect them to be at least accurate within say +/- 1 KH and +/- 1 GH. (based on my experience when preparing RO water and measuring). So I suppose the tanks could be in the KH 5-8 range and GH 7-10 range.

To be honest, I am rather clueless about what the TDS limits are for my specific plants and my specific fish. I suppose it depends a lot on what makes up the TDS in the first place. Both plants and fish seems to be doing good since I started to pay attention to the high TDS a couple of months ago.

Cheers,
Michael
 
jaypeecee said:
"Contains Iron, Calcium, Magnesium, Potassium, Sulfer plus over 25 other elements to nourish your aquatic plants.
Click to expand...
If that includes the 17 elements necessary for plants (maybe 14 as C, H and O are available from the water and its dissolved air) I wonder what the other 13+ (or 16+) are for?
:)
 
Hi @MichaelJ

Some time ago, I empirically determined a numerical relationship between KH, GH and TDS. It is this:

(dKH + dGH) x 18 is approximately equal to TDS (in ppm) if we're talking about freshly-buffered RO/DI water. Unless I'm overlooking something, this should hold true if we're considering carbonate and bicarbonate (as anions) + calcium and magnesium (as cations). Therefore, with your current KH and GH figures, this would approximate to 270 ppm TDS. Anything more than that is the result of all the other ions in your tank water.

Feel free to point out any errors in my reasoning. My professional background is in physics, not chemistry. That's my excuse, anyway!

JPC
 
jaypeecee said:
Surely, the answer lies with the substrate, doesn't it?
Click to expand...
That would be my prime suspect too. Apparently it contains lots of things, but we don't know what they all are, how quickly it releases them, or what factors affect the rate of release.
 
dw1305 said:
I don't know exactly how the dGH test kit works,
Click to expand...
Neither do I, but I wonder if acid and alkaline buffers would interfere with its reaction.
I will try to find out. I used to know exactly who to ask, but he is no longer with us. :(
 
I've used Eco complete for quite a few years in my Crypt dominated tanks as they seem to grow very well in it but I've never come across an issue like this.
In appearance it's like crushed lava rock although it does have smaller slightly crystalline particles but I don't know if that's just dust from the milling process.
 
HI JPC,
jaypeecee said:
Hi @MichaelJ

Some time ago, I empirically determined a numerical relationship between KH, GH and TDS. It is this:

(dKH + dGH) x 18 is approximately equal to TDS (in ppm) if we're talking about freshly-buffered RO/DI water. Unless I'm overlooking something, this should hold true if we're considering carbonate and bicarbonate (as anions) + calcium and magnesium (as cations). Therefore, with your current KH and GH figures, this would approximate to 270 ppm TDS. Anything more than that is the result of all the other ions in your tank water.

Feel free to point out any errors in my reasoning. My professional background is in physics, not chemistry. That's my excuse, anyway!

JPC
Click to expand...

Yes, your (dKH + dGH) x 18 = TDS for freshly buffered RO water seems like a good approximation to me. As as matter of fact, I am reading about 280-300 ppm TDS with my prepared RO water (targeting KH 6-7 and 8-9 GH). Whatever is making up the majority of the of additional 1200 ppm in the tanks is the mystery I suppose. If it would be something that is toxic in large quantities I suppose especially the fish would have shown signs of that by now.
 
Last edited:
MirandaB said:
I've used Eco complete for quite a few years in my Crypt dominated tanks as they seem to grow very well in it but I've never come across an issue like this.
In appearance it's like crushed lava rock although it does have smaller slightly crystalline particles but I don't know if that's just dust from the milling process.
Click to expand...
My Crypts are doing really well too... Yes, they do mention "volcanic grains" on the bag.
 
The screenshot of the back of the bag says in small print at the bottom:
Eco complete may elevate pH above neutral and may not be suitable for Discus sp., P. alta and sensitive freshwater shrimp.
Click to expand...
While the statement sounds like corporate ass-covering it does introduce the idea that it can release something into the water column and has the possibility to affect water chemistry. It is out of my experience area how this would interact with the acid and alkaline buffers that have been added to the water.
 
Maf 2500 said:
The screenshot of the back of the bag says in small print at the bottom:
Eco complete may elevate pH above neutral and may not be suitable for Discus sp., P. alta and sensitive freshwater shrimp.
While the statement sounds like corporate ass-covering it does introduce the idea that it can release something into the water column and has the possibility to affect water chemistry. It is out of my experience area how this would interact with the acid and alkaline buffers that have been added to the water.
Click to expand...
Yes, for sure. I never experienced any elevated Ph, KH or GH from this substrate though... or at least nothing my weekly 20% WC wouldn't smooth out. But who knows what else it might be releasing.

I will have to research if I could find a lab somewhere around here that could take a sample of my tank water and analyze it at a decent cost and tell me what makes up the TDS.
 
Hi all,
MichaelJ said:
tank water and analyze it at a decent cost and tell me what makes up the TDS.
Click to expand...
A lab. that <"has an ICP-MS"> would be able to do it. There are companies that run samples for marine aquarists.

Personally I wouldn't be too bothered. I'd just add less salts, watch plant health and change more water until the conductivity value comes down to one where you are happy with plant growth.

If I was a betting man, my money would be on a combination of SO4--, Na+, Cl-, HCO3- and Ca++.

cheers Darrel
 
dw1305 said:
Hi all,

A lab. that <"has an ICP-MS"> would be able to do it. There are companies that run samples for marine aquarists.

Personally I wouldn't be too bothered. I'd just add less salts, watch plant health and change more water until the conductivity value comes down to one where you are happy with plant growth.

If I was a betting man, my money would be on a combination of SO4--, Na+, Cl-, HCO3- and Ca++.

cheers Darrel
Click to expand...

Yes, especially since whatever is making up this ridiculously high TDS is apparently not hurting (at the moment at least) the fish or the plants, I will just do some extra large WCs over the next couple of weeks (without adding the Acid and Alkaline Buffers to the RO water) and lower my fertilizer. I am going to do two weekly 50% WC's and only add the Tropica Premium after the WC's (skipping the midweek Seachem Comprehensive and Trace) and see if that significantly drives down the TDS.

The only thing that worries me a bit is that if I essentially replace 50% with remineralized water with a GH of 8 and a KH of near 0 (as I am not adding the Alkaline Buffers) wouldn't that drive down my current KH of 6-7 to the 1-2 range (and eventually lower with consecutive WCs) where Ph becomes dangerously unstable?

Cheers,
Michael
 
You must log in or register to reply here.
Back
Top