Electrical Conductivity Meter

[shortman]

Guys,

Need some advise.

Any advantage of having the Electrical Conductivity Meter to measure the TDS of the water?

This is the item that I mention.



Thanks in advance.

[whuntley]

My Hanna tds meter (same as a conductivity meter but calibrated for tds) is my most frequently used fishroom measurement.

If the water tds (or conductivity) is abruptly changed, it can cause great distress in fish. This is because they need to adjust the cell-wall regulatory processes to keep the fresh water and the body fluids at different concentrations. That takes from a few minutes (for tiny fish) to a couple of days (as for salmon going from sea to river to spawn).

Whenever I do water changes or ship fish, I make sure that the tds is not different by a factor of two or more. That is, I don't take fish from 200 ppm water and dunk them suddenly in 60 ppm water. That would cause water to rush into gill cells and skin cells and make them swell, just like your finger skin does in a bathtub or sink when washing dishes. If the difference is great enough, they can actually rupture, and do permanent gill damage.

The effect is called "osmotic shock," and is the probable cause of about 90% of "pH shock" mythology. Ammonia handles the other 10%.

If you plan to buy one, get one with the greater range, rather than one with high resolution. My US$15 Hanna Instruments meter reads to 1 ppm, but only has a range to 999 ppm. I would prefer the one that is 10X less sensitive that reads to 1999 ppm.

BTW, get one calibrated for tds as that will let you communicate better with most aquarists, who don't know the conversion factor from microSeimens.

Wright

[Piscesgirl]

Wright,

You've convinced me -- I just put a bid for a tds meter on ebay. Anything else one needs to know about these meters? (I'm not much of the lab technician/scientist).

[shortman]

Wright,

Thanks for the info will order one like yours.

Cheers

[A.Rashid]

Kho,

For your info there is a Hanna company in Singapore, I think they are located at KL's area..

Hanna Instruments (S) Pte Ltd
161 Kallang Way #07-12/14
Singapore 349247
Tel: 6296 7118 Fax: 6291 6906
email: [email protected]
website: www.hannainst.com

[Piscesgirl]

I received my tds meter today -- can someone tell me what the readings mean?

My tap water is = 45 (ppm?)

My 55 gallon is = 131

My 29 gallon shrimp tank is = 71

Thank you!

[shortman]

I received my tds meter today -- can someone tell me what the readings mean?

My tap water is = 45 (ppm?)

My 55 gallon is = 131

My 29 gallon shrimp tank is = 71

Thank you!

Pisces,

I not so sure of the type of meter you have. Here is the conversion
1mg/l = 1ppm

I think 45 could be 45ppm and the tank reading is higher should be correct also as due to aging of the water and possible more dissolve particulars.

CONVERSIONS:
1CF = 1000uS/cm = 1mS/cm
2uS/cm = 1ppm
1oF = 10ppm of CaCO3 = 20uS/cm
1ppt = 1000ppm = 1g/L

Here is a list of meter available.

Best Regards

[whuntley]

I received my tds meter today -- can someone tell me what the readings mean?

My tap water is = 45 (ppm?)

My 55 gallon is = 131

My 29 gallon shrimp tank is = 71

Thank you!

Some tds meters read directly in ppm and the less sensitive (i.e., better) ones read out in 10 ppm in that last digit. First you must know which.

If your water is truly 45 ppm it is dangerously too low in life-giving minerals. You need to add Seachem "Equilibrium" to get it up near to 75 or 100 ppm. May need some baking soda, too, to stabilize pH.

OTOH, 450 ppm is pretty typical US well water and probably about 2/3 of that is true GH as CaCO3 equivalent.

In that case, you have too much salt in your 55G. Your shrimp tank is about where Robert Nhan used to keep Nothos.

That factor of 10 is pretty significant, so find out if 45 means 45 ppm or 450 ppm. If all else fails, you can get a liter of distilled or DI water, and add 100 mg of "No Salt" (KCl) and see if your meter reads nearer 100 ppm or 10. If the latter, you need to add a zero to all readings to be in ppm.

Wright

[Piscesgirl]

Thank you for the help

My water is very soft and comes out of the well with 28 ppm CO2. I don't add any salt to my tanks though -- so you don't mean true salt but minerals? The 29 gallon with the 72 I actually have to keep adding Calcium Carbonate for the shrimp, they use it up fast (but I don't want to add much more than they need because I keep Tonina plants that don't like a lot of kH).

I did add just a bit of baking soda to the 55 the other night to help buffer because I leave my pressurized CO2 on 24 hrs/7 days a week.

I'll pick up some distilled water this weekend and test.

The meter I have is the TDS 1 with automatic temperature compensation by Hanna instruments. Range is 0 to 999 ppm (mg/L).

[TyroneGenade]

I did add just a bit of baking soda to the 55 the other night to help buffer because I leave my pressurized CO2 on 24 hrs/7 days a week.

I assume you are fertilizing the plants as well? This could be the reason for the high conductivity reading. If you are adding baking soda you best be adding some potassium too to balance it out with the sodium. If you are going to buffer the aquarium you best employ some crushed shell or the like in the filter rather than dose with salts that will upset the chemical equilibriums.

but I don't want to add much more than they need because I keep Tonina plants that don't like a lot of kH

Well that explains why the one Tonia that made it through the post to me died... I planted it into sand bed made up mainly of beach sand! Hey, the Hygrophylia were thriving...

[Piscesgirl]

I really dont think that the 55 could possibly have that much salt -- it really has to be a straight reading. I fertilize a very tiny bit -- but certainly not the amounts that other planted tank people fertilize. My water comes out of the tap at 6.0 ph. I only added about a half a teaspoon of baking soda to that 55 tank. I added a pinch of potassium nitrate the day before yesterday because my nitrates were between 5 and 10 ppm, and about an eighth of a teaspoon of fleet enema for phosphate. Every once in a while I add less than a half teaspoon of Epsom salts for magnesium. But again, nothing like other planted tank folks do. I mostly let the fish food be the fertilizer, and slightly overfeed (as per Diana Walstad).

I have a 20 gallon long that has no fish in it and it showed with a TDS of 226, and there is Onyx sand in it (Onyx Sand buffers). I do not fert that tank, it just has a bunch of plants, snails, and worms, although I poured a little substrate in with the snails and I'm sure that there was argonite in it because they came from a Cichlid keeper. So, my thinking is that my TDS reading is a straight reading as opposed to X 10. Wouldn't you think? My 10 gallon also with a little Onyx sand and then gravel and snails (no fish) has 186 TDS, and I do not fert that tank either.

[Piscesgirl]

Well that explains why the one Tonia that made it through the post to me died... I planted it into sand bed made up mainly of beach sand! Hey, the Hygrophylia were thriving..

Yea, that would probably be the reason. My understanding is that Toninas like very low ph (preferably below 6.5) and Kh less than 3. I keep my shrimp tank around 6.5 ph and they do fine. There are some Tonina keepers that keep their tanks in the 5.0 ph range, which worries me very much, especially for the ones who keep shrimp in there, who need the calcium. But, I'm told they do fine..so I shut my mouth after awhile.


Oh yea, my kh is 1 out of the tap; so again, I'm thinking my TDS is straight not x10; but, again, I'm really quite bad with Science.

[whuntley]

You are correct, you have the same meter I have and it reads directly in ppm. Watch out, tho, for if the tds is over 999 you can get a false reading and the tiny little indicator that shows over-range is very hard to see. Try it on your bbs-hatching water and see what I mean, so you will recognize it when it happens in incoming fish bags.

You just have very soft water and should consider getting some Seachem "Equilibrium" to raise your critical electrolytes in all tanks. It doesn't raise KH so you can adjust that independently with the baking soda.

I only meant your 55 had salt if the readings were 10X, asd that's the only likely way it could be that much higher than your tap water (1310 ppm vs 450). 131 is just the added fish foods and plant stuff and to be expected, after a bit, with water starting at 28 ppm.

Wright

[TyroneGenade]

The lower the pH the higher the availablity of calcium. CaCO3 dissolves in acid water (from about pH 5 down I think... I know vinegar with pH 3.5 dissolves it).

The low pH coupled with fish feeding would explain the increase in ppm from the tap to the tank.

Oh, and 1/2 a teaspoon of bicarb is about 2 or 3 g (or 2000 or 3000 mg) which would give (lets say) 2500 ppm if dissolved into 1 L. A 55 Gal is about 210 L so 2500 mg bicarb would be about an 11 ppm increase from the baseline 45 ppm (56 ppm now). Another half tsp MgSO4 and you go up another 11 ppm (to 67 ppm) etc... daily feeding (another 20 or so ppm) and one can rapidly reach 131 ppm. That the conductivity is so low is a credit to your plants!

tt4n

[Piscesgirl]

Thank you very much for the clarification, Tyrone and Wright! I feel better now -- was getting a bit worried.

I have purchased Equilibrum -- but I haven't used it I do use Kent Botanic Grow in my shrimp tank -- a few drops daily, which has the magnesium and calcium and some iron like Equilibrium, just liquid (no copper!). I can use that in the 55 too I suppose, or the Equillibrium. I have calcium carbonate for the shrimp tank for buffering, that I use in tiny doses. I can use that in the 55 as well, but I was avoiding it because it does cloud the water for a bit while the baking soda does not.

Thank you again! I think this meter might be fun. I may have to find someone with a bag of fish to test Hehe I will be the mad-tester.