Invert suggestions

[dw1305]

Hi all,

I still haven't found a convincing use for measuring TDS.

If we call it <"electrical conductivity">, while agreeing that it isn't the parameter <"you would want to measure">, I think it does have some practical applications.

This is the bit where probability comes into play, after making certain assumptions.

• @Nick potts is right there is no inherent link between conductivity, dGH or dKH and no link between dGH and dKH either, but in most freshwater all three values are linked because <"they are all relate to the amount of dissolved limestone"> (CaCO3) in the water. <"In Torbay"> (where Nick resides) you can be 99.9% sure that the link for all three parameters is true.
• Calcium carbonate <"isn't soluble in water">, but it is <"soluble in weak acids">, and rainwater is a weak acid because of the amount of dissolved CO2 it contains. At 400ppm CO2, the solubility of CaCO3 (in pure H2O), means that water from a limestone aquifer has about 18 dGH and 18 dKH. The derivation of both <"GH" and "KH" is a bit strange"> but fully described in <"Larry Frank's "the Krib" article">.

This is definitely tangential to @BarrWarr's original question (and it is via PlanetCatfish <"Comprehensive Husbandry Protocol for Corydoras etc.. - PlanetCatfish.com">), but this paper,

Chiang, A., Haine, S.S., Goldring, R., Jungwirth, A., Siddiqui, M., Wilkinson, G., Manica, A. and Riley, R.J., 2024. Comprehensive Husbandry Protocol for Corydoras Catfish and Many Other Amazonian Species. Journal of the American Association for Laboratory Animal Science, 63(5), pp.472-479

says in the abstract (I can't access full-text):

...... In addition, these protocols are appropriate for a variety of softwater Amazonian species, and we present options for a variety of housing and husbandry conditions. On the whole, we suggest that, in a scientific laboratory setting, the use of remineralized reverse osmosis water is most appropriate and that in context, a single measure, total dissolved solids, can be used to monitor the water chemistry for water introduced to fish enclosures.......

I'm going to assume that they have chosen "conductivity" for the same reason I have:

• It is a "plug and play" meter,
• conductivity is unproblematic to measure and
• it is a linear scale - <"Guide to TDS">.

My take home message would be that, even though they are in a lab., they have still used <"an inferential methodology">. Again I'll guess that this is just because a conductivity value is accurate, unambiguous and doesn't require any interpretation.

cheers Darrel

 

[MichaelJ]

'm going to assume that they have chosen "conductivity" for the same reason I have:

• It is a "plug and play" meter,
• conductivity is unproblematic to measure and
• it is a linear scale - <"Guide to TDS">.

My take home message would be that, even though they are in a lab., they have still used <"an inferential methodology">. Again I'll guess that this is just because a conductivity value is accurate, unambiguous and doesn't require any interpretation.

Agreed

I still haven't found a convincing use for measuring TDS. 😉

Osmotic pressure is directly related to Electrical Conductivity (what we measure with our TDS meter). If you keep soft water fish - that is, fish adapted to low EC (i.e. low osmotic pressure) or livestock that are sensitive to or have a hard time regulating osmotic pressure, such as shrimps, you want to keep your EC low and make sure it is not fluctuating due to varying water parameters, decomposed waste accumulation etc.. Of course, adaptability, tolerance levels and so forth varies by species.

There are a lot of critical parameters you can't gauge from an EC measurement; such as a spike in Ammonia, a spike in toxic metals such as Copper etc., a spike in organics that are not yet decomposed, and of course the overall constituents of the minerals that makes up the EC in the first place.

One way of looking at it, is to think of the EC (TDS) measurement as a blood pressure measurement for our tanks... If a measurement is significantly outside a datum range you know something is off. You can't tell exactly what or the underlying cause from the number you measure, just as you can't tell from a high blood pressure reading, but you know something is going on that warrants a further analysis and possible corrective actions.

Cheers,
Michael

 

[geotom]

I really love the Blue Dream/Blue Velvet shrimp (Neocaridina davdi). They are beautiful when you get that deep blue colour.

 

[hypnogogia]

I really love the Blue Dream/Blue Velvet shrimp (Neocaridina davdi). They are beautiful when you get that deep blue colour.

They really are.

 

[MichaelJ]

I really love the Blue Dream/Blue Velvet shrimp (Neocaridina davdi). They are beautiful when you get that deep blue colour.

For sure... just make sure you stick with that one color if you want the offspring to maintain that color - some variation will always occur, but if you mix various colors your going to end up with very gray- or brown'ish individuals).

Cheers,
Michael