Water tests with less water and less chemicals?

[chesspupil]

I am looking to make my test kit stretch about two to three times (OR MORE!) further and I think I have a solution:

With a pipette I should be able to obtain very precise water volumes and since the color card for test measuring is based on the water being viewed through the 5ml cylinder I can measure my reduced water quantities into the 5ml cylinder based on what water ratios to drops of chemical are needed

So I am curious if anyone has any experience with using smaller quantities of chemicals in this manner.

For example:

PH test

Test wants 3 drops for 5 ml of water

Which means the quantity of water for 1 drop would be: 1.66 ml

With a pipette I measure out that amount into the cylinder that is normally used and add one drop.

Ammonia test

Test wants 8 drops of parts one and two to 5 ml

for two drops of each need 1.25ml

I have tried cutting the 5 ml down in half and the drops in half and tested my results side by side and I think I end up with the same results as the full 5ml tests.

Anyway if you have a source for pipettes accurate to .01ml that would be helpful.

[850R]

I don't know of a pipette source but I am curious why you would purchase something as meticulously developed and researched as a test kit and then want to use it in any other way than as directed in the instructions that come with it.

Even if you do manage to make it last [And don't have suspect readings] It may just be out of date before you run out.

I really can't see what you gain after all the extra effort. . . Just saying.

[Fisharefriends27]

Can't it possibly affect the results I agree with 850r

[smaug]

I have 75% of the same api master kit I bought 4 yrs ago.Ill sell it to ya cheap :hmm3grin2orange: .After your done cycling a tank you really only need to test once a month if everything looks good to the eye.

[Lady Hobbs]

This makes no sense to me at all. As smaug says, once you get your cycle, it's seldom you even use the test kits when you do your normal weekly mainenance. This is like using only part of your medications to make them last longer when a higher dose has been been tested and proven to be the dose needed.

[Brhino]

Additionally, reducing the volume (even assuming your procedure is correct) reduces the margin for error or variability, and makes it more likely you will get an inaccurate reading. Agree with the others - your test kit will likely expire before it runs out, unless you are doing many tests on many tanks. In any case test kit reagents are a tiny fraction of the costs associated with fish keeping... don't mess with what works.

[850R]

After your done cycling a tank you really only need to test once a month if everything looks good to the eye.+1

It's a courtesy test monthly unless I see something goofy or find a body or something.

[lotus flower]

Anyway if you have a source for pipettes accurate to .01ml that would be helpful.

Yes. I've used pipettes that are that accurate before in my Microbiology and Molecular Biology laboratories. Unfortunately, they run about $2,000.00, conservatively. The more accurate a pipette, the more expensive it becomes.

Trust me, you're better off buying the new test kit when you run out of chemicals. I test every 2-3 days, even with my tank cycled, and my kit has not run out in over a month.

Edit: Okay, apparently some TA's have exaggerated when stating replacement costs. Here's what we use to micropipette: [Only Registered Users Can See Links.]

It's about $315.00 for a good one.

[gm72]

Are we really talking about stretching a test kit that only costs around $20? A $20 test kit that lasts for potentially months on end?

[chesspupil]

I guess I stepped up in front of the firing squad on this one...

Yes, I agree the margin of error goes up as one cannot obtain a consistent drop size.

I have seen ul pippetts for less that 10$

[850R]

I guess I stepped up in front of the firing squad on this one...

Yes, I agree the margin of error goes up as one cannot obtain a consistent drop size.
It's not a firing squad by any means, It just seems like a ton of effort for minimal at best gain.

[gm72]

To be honest I test my water maybe once every 6 months. Maybe. This is because I tested the heck out of it as the plants started to take off. I know that most of my tanks get to NitrAtes of about 10 weekly. I do 50% water changes weekly and all is well. I do start testing more often if I add new stock just to make sure I'm on top of any bioload problems.

[Lady Hobbs]

Buying products online is far cheaper than in fish stores, too. My API test kits are $18. I test every "now and then" for nitrates in my planted tanks. That's it.

[irob]

When I took biology we just used glass pipettes with a little thumb wheel at the top. Those can't be too expensive.

If anyone has a source for the cheep pipettes let me know. I would love to have one of those for more exact liquid measurements when adding water conditioner or even medicating my 3 year old boy.

And my API test kit is pretty old too. I broke one of the glass tubes so now I only have 3 and it's a pain. Can't justify buying a new kit for one glass tube though.

[BrandonBCA]

I've got to agree with the consensus here, sounds like you're going to more trouble than will benefit you.

The API test kits are only really good for about a year after opening for the most part, and using them as directed they will more than likely last longer than that even with weekly testing at the recommended levels. Daily testing with some will get you about 6 months, others close to a year. When they say 150-250 tests per kit they mean it.

Your pH test kit is based on the bromothymol blue reaction which increasing the drops will only increase resolution, and not skew results(other than making operator errors more likely). If you really want to stretch it you could add a drop to 5 mL and still get the same degree of accuracy, but a less bold color. I imagine the rest of them are set up so that the reagents are in excess up to the upper limit of the color chart, so your accuracy shouldn't suffer using the same volume ratios. Still seems like an unnecessary amount of effort, though.

As for the broken tube, API sells replacement tubes in packs of 3 and 24 online, and some petsmarts carry the 3 packs. No need to buy a new kit for new tubes, and always a good idea to have extras on hand if you plan on doing a lot of tests.

For me personally a syringe accurate to 1/4 mL is plenty of resolution. Most hobbyist test kits are more for qualitative purposes than quantitative purposes, so accuracy of water volume isn't really going to help you all that much. Plus, using pipettes you'd need to buy a bulb, stand, and other auxiliary equipment. The only tests I could see that really helping with would be the titration tests(kH, gH and direct CO2 tests) and then it would take some redesign on the reaction order. Still more effort than it's worth.

[Zerileous]

If you want to go old-school i think the pipettes and pipetters are fairly cheap, but digital pipettes are not. And they are so much easier to use.

Also, tbh I think the test has a fairly high margin of error. I've measured 5 cc with a syringe before and it actually comes out at least a mm below or above the line by the meniscus (I don't remember which). This was also a larger (60 cc) syringe so it may not be all that accurate either, but generally there is just a margin of error with that sort of thing. Even liquid graduated med cups are off when you check it with a syringe.

ps. 1 cc = 1 ml, just to clarify.