Hey everyone, as the heading says, I was wondering what are the detrimental effects of having TDS which is too high or too low? Does it make it hard to molt? Does it effect the shrimp while its hardening a new exoskeleton? Is it bad for everyday life? Sorry for all the questions but I'm just trying to get my head around what problems are caused by the wrong TDS. I've read up on what TDS is & does, I just want to know how it effects shrimp? :encouragement:

Excellent question I'd also like to know the answer as I'm very new to the whole TDS/EC side of things and will be moving into CRS/CBS etc in the next month or so

If you have a high TDS, it basically means that there is more dissolved minerals than there should be. An example of a mineral that will raise TDS is any of the nitrates, and as you know, nitrates are toxic at high concentrations to shrimp. Another is NaCl, table salt, again, at high concentrations, toxic to shrimp. Magnesium Sulphate is another, high concentrations means very hard water, makes it hard for shrimp to moult. Calcium Sulphate, same thing.

Similarly, a TDS too low means there are a lot less dissolved minerals than there should be. The major issue with this is Calcium and Magnesium which the shrimp need to moult.

Ok thanks, so does that mean that the shrimp are more likely to die after moulting due to high or low TDS?

Hey squiggle.

That is exactly what happens..

Sometimes the shrimp may find it difficult to get out of there shells to molt..

or

They may not be able to harden there fresh shell once the old one comes off..

Both instances are not good and shrimp will most probably die..

Both high and low tds are not good and shrimp will have problems molting..

Hope that helps

Low TDS will mean that they are more susceptible to a bad moult and as such have a higher chance of mortality. A TDS that is too high will not only increase the chance of a bad moult, it also means that your water parameters aren't within the safe limits for general wellbeing of your shrimp. If TDS is too high, shrimp can die from nitrate poisoning without ever having to moult.

Awesome guys, thanks heaps. This info helps a lot, I'm currently trying to reduce the TDS in my tanks but I know the nitrates are almost zero, gh is high but kH is almost zero, it must be the other dissolved salts from previous inhabitants in the water keeping it high, thanks again guys :encouragement:

Try using distilled water as top ups.. will will help lower it considerably

Yeah, I'm using rainwater for the cherry tanks, it's TDS is about 40ppm & I'm using some RO water Aquathumb gave me for the CRS tank, they are coming down slowly as I'm only doing about 5% a day :encouragement: