question on water hardness and leaching

[anewbie]

Ah OK you said TDS 17 and EC 26, they were both TDS then?

No both were ec; i only use my ec pen these days (hanna). If i wrote tds somewhere i should have been ec.

 

[Mazan]

Well in that case EC is still very low at 26.

 

[dw1305]

Hi all,

I'm not sure i could measure gh or kh at ec 26 (tds 13).

You don't need to, that is an incredibly small amount of ions, so they are both (dGH & dKH) less than one.

I don't follow you - I measured 17 and yesterday i measured 26 so it raised from 17 to 26 sitting idle in the cup for a ~week.

Conductivity is temperature dependent as well, higher temperatures cause increased electrical activity.

And you took the sand from your tank. I'd expect this to be the result of biological activity, not of minerals dissolving into the water. That would have brought much higher rises.

Likely.

Well in that case EC is still very low at 26.

That is it, it is a tiny addition of ions.

cheers Darrel

 

[Mazan]

The figures I posted earlier were TDS not EC. At the moment the dwarf pike tank is reading EC 34.

 

[anewbie]

Today the EC was 34; of course two things - a small leaf stem was discovered and about 20% of the water has evaporated; so i guess if there is leaching it is not horrible though at this point i don't think there is benefit to continue esp with the evaporation.

 

[Ben Rhau]

You could always replace the evaporated water with distilled and/or cover the container

 

[Ben Rhau]

Probably the bigger issue is to adjust your measurement for temperature, unless your room/cup is the same temp as the tank.

 

[anewbie]

Probably the bigger issue is to adjust your measurement for temperature, unless your room/cup is the same temp as the tank.

The tds of the cup vs tank is not relevant per sey; what is relevant is the change of tds over time in the cup to determine if the substrate is an issue. Since i will buy a jug of distill water tomorrow and restart the test the jug will be in the same room as the cup and therefore the same temp (though i'm not sure that matters either).

You might be suggesting that the temp impacts leaching from the substrate and i suppose that could be true but the room is 72-74 and the tank 78.... so not a far difference.

 

[Ben Rhau]

That sounds like a good plan. For relative changes over time, temp is relevant if the temp of your cup is changing. So it may help to record that as well.

 

[anewbie]

Ok i reset the test today - with distill water - when i put in the distill water it was ec 5; when i stired up the substrate with a metal probe it went to 10 (which i consider insignificant change). We shall what it is next week.

 

[MacZ]

Ok i reset the test today - with distill water - when i put in the distill water it was ec 5; when i stired up the substrate with a metal probe it went to 10 (which i consider insignificant change). We shall what it is next week.

I think there will be just as much change from bioactivity as in the last attempt. I'd call it quits and consider the sand more or less inert.

 

[anewbie]

I think there will be just as much change from bioactivity as in the last attempt. I'd call it quits and consider the sand more or less inert.

We shall fine out in a week

 

[MacZ]

Allrighty!

 

[anewbie]

Welll...... today a week later the ec was 27 @ 76.1

I'll do one more test with substrate out of hte bag in a week or so - as i need to open another bag for my chocolate aquarium (my chocolate keep digging holes all the way down to the bottom).

 

[Ben Rhau]

Did you do a negative control with no substrate?

 

[anewbie]

Did you do a negative control with no substrate?

Will start that now.... (i.e, no).

Ok i used ro water instead of distilled water - the base is ec 9 @ 74.5

 

[Ben Rhau]

In the future, it’s good to do all the treatments at the same time so the only thing that’s different is the thing you’re varying. i.e., the water starts the exact same, temp is always the same, etc.

 

[anewbie]

In the future, it’s good to do all the treatments at the same time so the only thing that’s different is the thing you’re varying. i.e., the water starts the exact same, temp is always the same, etc.

I know but too hard. I only have one glass cup for example there is a story behind that glass cup as i was visiting a friend in copenhagen many years ago when the world was still sane. I don't drink beer but he loves beer so being it was october we went to some beer fest thing where they had a gazillion things of beer and free cups

 

[Mike Wise]

Not really a good excuse IMHO. Just go buy 2 inexpensive identical glasses at any department store.

 

[Ben Rhau]

I use mason jars.