Got my potassium test kit

[wasp]

Finally got the potassium test kit, & done some tests.

The kit is a colour change one so it's a bit tricky to interpret it relies on the eyeometer :lol:

There is a colour strip starts dark at one end and slowly fades towards the other end. After mixing the reagents you wait 4 minutes, and the mix turns a watery milky type colour. You then put it on the colour strip at the dark end, and slowly slide towards the other end, until you can no longer see the colour strip through the mix. Stop at that point, & it gives you your potassium reading.

I found the exact interpretation quite hard as I'm staring through this stuff trying to see the colour strip & it's a bit tricky getting the exact pint where it fades out totally. It was somewhere from 300 down to 250 for me, but another reefer who was with me could see it at 250. So I tested NSW knowing that is around 380, and got a reading of 300. However what I realised was that was at my desk by the window in quite bright light, I tried it in a less brightly lit part of the room & got between 400 to 350, which would be the correct reading. In any case my tank water is the same as NSW.

So I would say due to it being hard to interpret, the kit is really a guide only, although using NSW as a standard does help say if the water is where it should be.

I was told by someone associated with the marketer of the kit, that they could have done a more accurate, easy to interpret one, but it would have been more expensive than they felt people would pay. With a little practise i think I can probably get to where I can get a worthwhile result with this kit.

[petplanet]

Brand? Cost?

[wasp]

korallen-zucht, swapped it.

[reef]

have you seen these wasp.

http://www.hannainst.co.uk/acatalog/HI-93750_Potassium_Meter.html

Might be better than having a random test kit. Pottasium must be very hard to read due to no quality test kits available, i dont think even lamottee or hatch do regent test kits for pottasium. the reagents might be very unstable

[wasp]

Another person who does not go to bed at night! :lol:

The Hanna looks good an electronic read rather than an eyeometer would be a definate advantage with this test.

Only trouble from a marine aquarist point of view it only reads from 0 - 50 mg/l, not the 380 or so we are interested in. But the idea is there, pity they don't do a higher range meter.

Been doing some experimenting with the kit, instead of the 1 ml of tank water I used 1/2 ml, + 1/2 ml DI, and the result has tested at below the 200, as low as the test can go. Did this because all the other tests were fairly similar i just wanted to be sure it will give different numbers.

Reef I heard by the grapevine you may have some kits coming. If that's correct it will be interesting to see how they go.

[reef]

I have a few Pottasium kits to trial out. They will be pretty much the same as yours.

Pottasium is so hard to test that is why the hanna meter only goes to 50mg/l

[lduncan]

I think these potassium kits are using sodium tetraphenylborate, which forms a precipitate with potassium.

What do the reagents smell like? Phenolic?

I would have thought that it would be well suited to a colometric style test.

The reason why there are no potassium kits around, is because no one cares about potassium levels ;-) ... unless maybe you're a doctor.

[bychineva]

hi wasp see if this links help in anyway...http://zeovit.com/forums/showthread.php?t=7067

[wasp]

Thanks Bychineva, good link. Looks like I’m not the only one finds this test hard to read.

When I have a few more minutes I am going to post on the RC chemistry forum & find out how to make a potassium standard calibrating mix, with the potassium chloride I have, so that I can know exactly how to read the kit.

[lduncan]

Disolve 15.2 grams of potassium chloride into 1 litre of water. Mix well to dissolve.

Then take 5 mL of this solution and dissolve it in 100mL of water.

The resuting solution will be around 400mg/L K

Just know, that without acurate scales it's hard to make an accurate standard. For example, following the above directions, then if you make a 2 gram error in weighing, then that effects the standard by about 50ppm.

Layton

[jetskisteve]

Wasp my scales weigh down to 1 gram ( not drugs )

[wasp]

Nice to see a positive post from you Layton. Good research. You can be a very helpful guy!

Sometimes! :lol:

And Jetski, thanks. I may take you up on it, depending. I suspect my potassium chloride may have absorbed a little water, which would affect measuring it by weight.

There is a thread here http://reefcentral.com/forums/showthrea ... did=955885 will see what comes of it, may be able to measure it by volume, which could be a safer option.

So, if no joy on measuring by volume, I'll take you up on the weighing thing Jetski.

Oh, and just out of interest, for what lawful purpose do you own such a device?

[Feelers]

I suspect my potassium chloride may have absorbed a little water,

You could always put on the oven mits and get baking... :lol:

[lduncan]

It's easy if you know what your talking about wasp ;-)

It's a two second calc to work that out, no research needed.

Doing it by volume is impractical, it's far more inaccurate. If you're worried about water (it's not very hygroscopic like calcium chloride is), you can dry it in the oven (couple hundred for 15 min should be more than enough time).

[wasp]

Thanks both, yes I had considered baking it.

And Layton, what a guy! So good I can talk to someone who knows what he is talking about! AND do a two second calc!!

[lduncan]

:roll:

Well, don't worry wasp, if you find my advice too hard to swallow, i'm sure Randy's will do the trick too.

[wasp]

Not at all Layton I will happily swallow your advice!

I'll let the other thread run a couple of days and then see what is the easiest method for me. Being by nature lazy, I will do whatever ends up being easiest.

Hey I do appreciate the help, I'll keep you posted how it goes.

[reef]

So lovely when love is in the air

[lduncan]

It's just the patronising snarky comments which make me not want to bother posting in the first place.

I tried to design the mix above to be practical to make, based on workable volumes, weights etc to make it as acurate as possible given the situation.

Layton

[wasp]

Didn't know you such a sensitive guy Reef! :lol:

Yes me and Layton have known each other for several years now, like all relationships it's had it's moments :lol:.

And Layton, "Patronising", "Snarky"!! Whoa!!!! Could this be another "moment"? :lol:

Truely, I appreciate your help, your formula would be practicle to make, and I am happy to swallow your advice!

[ZEOvitANZ]

Alastair, how about taking a reading off natural seawater then aim to keep your aquarium at the same value

Regards

Brendan

[wasp]

Yes good thought about the NSW, done that, but just thought I'd like a standard test mix also.

Laytons formula is correct, will be easy to make, so I'll go with that. Like I said, he can be very helpful.

Sometimes! :lol: .

I'll update in a few days with some more testing results.

[wasp]

Help needed!!

I'm going to make Laytons Special Recipe, but turns out Steves fine scales is the set he sold!

So, anybody else local got scales that can weigh 1 gram?

If not i know where I can still do it but will have to call in a favour :-? .

[wasp]

Hey Layton!

I'm going to make your recipe later tonight but first a couple of questions for you.

Your recipe is to make a mix at 400 ppm, but I want one of 380. So, according to my 2 hour calc (just kidding :lol: ), instead of using 15.2 grams, I should use 14.44. That sound right to you?

Also, the bit where you said to dissolve 5 mls in 100 mls of water, you mean add the 5 mls to 100 mls making a total of 105 mls, or did you mean add the 5 mls to 95 mls making a total of 100 mls?

[lduncan]

Hey Layton!

I'm going to make your recipe later tonight but first a couple of questions for you.

Your recipe is to make a mix at 400 ppm, but I want one of 380. So, according to my 2 hour calc (just kidding :lol: ), instead of using 15.2 grams, I should use 14.44. That sound right to you?

Also, the bit where you said to dissolve 5 mls in 100 mls of water, you mean add the 5 mls to 100 mls making a total of 105 mls, or did you mean add the 5 mls to 95 mls making a total of 100 mls?

Yes 14.4 grams is close enough. You can add the 5 mL to 95 mL of water is more acurate, but the error from a 5mL difference is going to be insignificant in the scheme of things.