Conductivity. (Split this from the Peat)

[D.J]

Thanks for the info Sunshinediscus, but I am going to ask a silly question.
What is conductivity and how do you measure it?
Is it the same as german hardness?
Right now I am using Sera super peat, only a handfull which I put into a mesh bag and hang inside the tank to treat 150 litres. I started on Thurs which my ph was 7.18, today my ph is 7.02, I think I am going to put in more to try to get it down to about 6.9.

Donald.

[sunshinediscus]

Hi DJ,

Conductivity is a measure of the ability of water to conduct electricity. For instance a water that has a high mineral content ( including salts, kh and gh ) conducts electricity better than water that is poor in minerals ( distilled water) . So all a conductivity meter does is passes a current between 2 electrodes and then measures the ease of which this happens. Pure water will have a conductivity of zero ms (microseimens) and sea water is about 3000 or so from memory. Conductivity is a true measure of the mineral content and is the preferred method to test water by people breeding soft water fish such as discus. While kh and gh are useful neither will test for the total amounts of salt. It is possible to have ideal kh and gh conditions for breeding yet the eggs may not hatch or hatch very poorly due to a high salt content. A conductivity meter takes the guess work out of it. The meter also has other uses like testing how well your R/O unit is operating and the suitability of certain acids and buffers when breeding discus.

Hth

[Proteus]

..and, out of curiousity, what is the ideal conductivity for keeping and/or breeding Discus???

[sunshinediscus]

Hi proteus,

Ideal conductivity for breeding is somewhere in the range of 80 to 150ms although good hatch rates can be had in higher conditions as well. Top breeders from the past like Eduard Schmidt focke bred his fish at around 80 and other top breeders like Gobel also breed in very low conductivity. Lower is better but comes with its own problems especially concerning stability of the PH. It's interesting that the natural waters of discus has a very low conductivity, i have seen reports below 20 and rarely does the conductivity go beyond 100.

Keeping discus is a different matter and the discus can be raised in a relatively high conductivity with no ill effects, even above 600 ms will not cause any dramas and i'm sure plenty of people keep the discus in higher levels still with great results.

I guess whatever works for the breeder is the ideal and each breeder will have his own ideals, keeping and breeding is not an exact science and your own experiments and experiences is the best guide.

[Escher]

Isn't it funny? I mentioned few days back to be carefull 'cause the pH can crash. So it does in my standard 4footer. :? but now that I am trying to lower the pH in my new 7x2x2, I can't get lower than 6.95!!! :evil:

[flukes]

I read somewhere that it is good for juvi's too have a conductivity of 200+ and as they get older it drops, ie sub-adult 150-200 and for breeding anywher between 50-150.
Although i havent got a TDS meter i would really like to get one now.

Rod,
So the main difference between using conductivity and kh/gh is that TDS measure the total disolved solids in the water and the kh/gh is more of a broad reading on the hardness of the water. Is this correct? So really using TDS as a means to finding hardness is alot more acurate than using kh/gh??
Inlighten me..
:wink:

[sunshinediscus]

Hi Scott,

Yes that is correct, conductivity is a true measure of the total dissolved solids. For instance if you were to have a kh of 3 and to each liter of water you added 35grams of salt ( i used that figure as it makes the same strength as sea water) and then tested the water you would still have a kh of 3 and what would appear to be ideal breeding water for discus. The same goes for acids and buffers, if you were to use monosodium phosphate (a commonly used ph adjuster) to lower a high ph then your conductivity could go as high as 600ms or more while the kh stays the same and of course your hatch rate could be affected or even stopped at that conductivity.

personally i keep my fish at around 300ms and only for breeding is it reduced. After spawning when the babies are free swimming i no longer use breeding water to do water changes but regular 300ms water so gradually the conductance will rise until when it is time to move the babies they are living in the same water as my non breeding discus. If i wish to respawn that pair then i perform a 50% water change with straight ro then do the daily water changes with the breeding water from then on. There is no stress to the fish with sudden changes in the conductivity and quite often they will respawn within a few days.

hope that answers your question.

Rod

[flukes]

Thanks for the info Rod,
Just a few questions, where can i find TDS meters in Australia and is there any other way to change TDS's without using an R/O.?
Also is your R/O unit hooked up to the house water supply, just wondering does it need the pressure from the house tap line too work? Or is there another way around it.

If anyone has information on where to get r.o units or tds meters, could you please reply.

[flukes]

Actually found a great site with Ph, TDS and even Chlorine meters.
Anyway take a look.

http://www.vendart.com/index.html

Just a few other question some meters also read ORP and EC just wondering what these are and how important they are in an aquarium.
The meters i am looking at dont look cheap for one too do ph, TDS and EC is 200+. Well still some more researching too do.

[flukes]

Sorry doing some research and finding more information as i go.
For all us in melbourne i have found a great company located in Boronia that not only sells TDS/EC/Ph and temp meters but it also does lab test on water, so you can have a more in depth look into what your water actually contains.
I might actually take a sample of my water down there on the weekend and ill post the results here, For a TDS/EC meter your looking at about $100-$150, and ph are as low as $80-$150 or you can go too DSE and pick the one reviewed in another post.

For all those in Sydney, i found a company that is located in Box hill that seems too have all the neccessary meters and also does some owrk with R.O's.

And for Queenslanders there is a Milwalkie distributer, i forgot the loaction but i simple web search will find you the page.

HTH.

Think i might have to invest in an R.O unit!!

[sunshinediscus]

ec meter is electrical conductivity.

orp is a redox potentiometer (<<spelling :? ) That measure the oxidization potential of the water. A higher redox reading means greater capacity for oxidization. It is usually raised by the use of ozone and is not commonly used in discus tanks although i suspect it is something that we will see more of in the future.

Yes an ro is usually hooked up to tapwater preasure although there are units that come with pumps for well water or river water. Other methods to reduce conductivity are ion exchange resins and peat moss and pure rain water has a zero conductivity.

I have a pinpoint conductivity meter, aquasonic is the aussie distributor of them but they are quite expensive. Last for many years however so worth it if you are into breeding in a big way.

[flukes]

Thanks Rod,
Iam going to visit this guy in boronia too get my water tested and see if an R.O unit is needed. I really dont want too install one in this house as i dont think i will be here long enough to make it worth it,

[flukes]

Spoke to the guy in boronia,

He said he just tested his water and it had a reading of 41ppm TDS. Although he uses a different water company than me. He said there wouldn't be too much of a differnce between the two companys.

But ill find out for sure when i go get some tests done.

Just for the record he uses Yarra Valley and iam with South East water, (for all you victorians)

Anyway ill post the results after i get the tests done.

[rex82]

so does an R/O unit lower the conductivity of the water, my tds comes out at 30ppm, i still have probs with eggs going bad after approx 48 hrs.
PH= 6
Temp=29
ammonia= nil
nitrite=nil
nitrate=10-15 ppm
i have four pairs on the system and it is a 600L system (inc sump), changing 50% twice per week

any thoughts?