Testing water: drops vs. strips

[HopeGR]

I have a 20 gallon with ten fish and a handful of fry. In my attempts to efficiently feed the fry, I may overdo it to the point where the nitrates rise.
Ammonia, however, stays at zero. What I did is use the following strips: API, Tetra, and this one S & J I bought from Amazon. Daily tests with the strips give me a nitrite reading of zero, whereas the nitrate hovers between 25 - 40 according to the colors below.

As I'm really invested in this hobby, I thought to spend and buy the drop tests of Nitrate and PH, as well as Ammonia. The Ammonia is yellow, the ph reads a blue - not light blue - but blue, indicating a 7.6 - 7.8 reading. And the nitrate drops showed a reading of 15 - 20 indicated in the card below. So the strips and the drops matched.

I did a water change. Then, 48 hours later, as in today, I did the strips again and the drops, and the strips were reading identical as before, where as the drops for the nitrates were yellow - meaning zero.

So, could someone explain why the water change brought down the nitrates to zero according to the drops, but not the strips? Which is more accurate? As one who has a family business in pool construction, I am a bit familiar with water tests, and always advised customers the strips were never as accurate as the drops we use at the office to test water. Logic tells me the same is applied here. Am I wrong?

 

[Aiken Drum]

API liquid test kit? You really have to shake the heck out of bottle #2 on the nitrate. Maybe even bang the bottle on the countertop. If it isnt shaken enough it will read 0ppm nitrate.

 

[HopeGR]

API liquid test kit? You really have to shake the heck out of bottle #2 on the nitrate. Maybe even bang the bottle on the countertop. If it isnt shaken enough it will read 0ppm nitrate.

Interesting, no I did not know about the shaking. Was it coincidence then that the first time both read the same reading? I will try again tomorrow. Yes, it is the API test. Needless to say, it made me nervous to read that gloves and masks are recommended when using this product!

I find myself changing the water 20-25 percent every 3 -4 days and I believe I was told that this is not recommended.

 

[Aiken Drum]

Interesting, no I did not know about the shaking. Was it coincidence then that the first time both read the same reading? I will try again tomorrow. Yes, it is the API test. Needless to say, it made me nervous to read that gloves and masks are recommended when using this product!

I find myself changing the water 20-25 percent every 3 -4 days and I believe I was told that this is not recommended.

You have to make sure you follow testing instructions for liquid tests precisely. Fill the test tube with 5mm, add the correct # of drops, shake bottle #2 vigourously for 30 seconds and the test tube for 60 seconds, read after 5 minutes in good light (preferably daylight) against a white background. And even then dont expect your test to be 100% accurate. Its good enough to identify any issues however.

I seem to recollect that i was doing the nitrate test incorrectly when i first used it but still got readings to start with, and after 2 or 3 tests started to get 0ppm readings and checked the manual properly. Started shaking the heck out of the bottle #2 and the nitrate came back. You need to get the white residue into the solution, you should be able to see it in the drops you add from bottle #2.

As for you having to do 2 x 25% water changes per week to keep your nitrate under control i dont see a problem there. Your stocking is likely on the high side if you need to do this though. I tend to do 50% weekly and doing 2 x 25% changes would be less stressful on the fish than 1 x 50% change. Obviously smaller and less frequent changes are preferable if you dont need to do them, but if you have high stocking then its needed. Do you have live plants? That would help controlling nitrate and might mean you can cut down on water changes. 30% weekly is a good target.

Edit: I dont wear gloves or mask to do the testing. Probably just a precaution against litigation.

Edit 2: If done properly, its generally accepted that the liquid test is more accurate. Also, though more expensive up front, in the long run liquid tests are much cheaper as you get 100s of tests. Dont keep buying strips, just get the liquid tests.

 

[Caliban07]

Interesting, no I did not know about the shaking. Was it coincidence then that the first time both read the same reading? I will try again tomorrow. Yes, it is the API test. Needless to say, it made me nervous to read that gloves and masks are recommended when using this product!



I find myself changing the water 20-25 percent every 3 -4 days and I believe I was told that this is not recommended.

After spending lots of time on the UK aquatic plant society and speaking with some of the members there with a scientific background, it would appear that testing nitrates is problematic even with superior testing methods under laboratory conditions. Apparently, there are just too many other anions that can interfere with the liquid tests.

The 40ppm maximum we strive for is also based on outdated information. I have read of occurrences where someone has accidentally dosed nitrate levels up in the 350ppm range for a couple of weeks and didn’t record any issues with live stock. That said, there are studies showing injury to certain species at a lower level than this but also at a much higher level.

It is this uncertainty between both testing and not knowing how much nitrate my fish can be exposed to that made me want to keep nitrates as low as possible.

I’m with Darrel on UKAPS in that a don’t test but I can be confident that my nitrates are low because I have water with very low conductivity which means I have little of everything in solution. I also use plants and rooted floating plants as well as floating plants. I figured since nitrates where naturally low or often times undetectable in natural waters I’d want to keep my level that way too and since we have the nitrogen cycle, my tank produces nitrates 24/7 so my plants should be good.

Anyway my point is, it’s likely that the test kits are providing inaccurate readings which is causing you an unnecessary dilemma. If you’re worried about changing water change much less more often. Fry will most likely find food around that tank if you have some moss or plants in there. They don’t need to be constantly fed.

 

[Caliban07]

If you watch this video from about 1:15 you can see all the life that feeds on this aquarium mulm. Pleco babies snails, probably tiny fry.

Yep, this is the same stuff that people vacuum or squeeze out of their sponges every week. [emoji846]

https://youtu.be/6rRVbXeq_EY

 

[HopeGR]

Re:

Thanks to both for the help. Perhaps I am overstocked, and I'm trying to find a place to set up a ten gallon for the fry since they are still small. I haven't lost a fish since mid Nov, and lost pretty much all ten in Oct when I upgraded to the ten gallon due to my lack of knowledge on tank cycling. The 20 gallon seems much more manageable since especially I have learned more about maintaining the tank.
Also, I think I misunderstood the directions - now that you pointed it out, it did say to shake bottle #2, but somehow I misunderstood it by thinking it said shake the vile before entering drops of bottle #2. My hesitation sometimes leads me to misread things. And I suppose the water changes every 3 -4 days are ok. You are right, the strips are definitely more expensive. Also, is it me or does anyone else also think the Tetra strips are a bit more sensitive in their readings?

 

[fishwonder]

You are right, the strips are definitely more expensive. Also, is it me or does anyone else also think the Tetra strips are a bit more sensitive in their readings?

Cut those strips lengthwise and get 2 for 1. I use the strips and they work just fine. If I need a more definitive answer, liquid works better.

 

[HopeGR]

Cut those strips lengthwise and get 2 for 1. I use the strips and they work just fine. If I need a more definitive answer, liquid works better.

That's an idea too!

 

[fishwonder]

The 40ppm maximum we strive for is also based on outdated information. I have read of occurrences where someone has accidentally dosed nitrate levels up in the 350ppm range for a couple of weeks and didn’t record any issues with live stock. That said, there are studies showing injury to certain species at a lower level than this but also at a much higher level.

It is this uncertainty between both testing and not knowing how much nitrate my fish can be exposed to that made me want to keep nitrates as low as possible.

I think this is very true. I had my 75 gallon tank suffering from old tank syndrome with 20-25 African Cichlids three years ago. Water changes every 6+ months, added water only when evaporation occurred. I decided to get the tank straight and tested and found my nitrates at the over 160 ppm mark. So I changed 70% water and tested again. Still over 160 ppm! This means nitrates had to be over 300 ppm for a long time. Well I decided to find out why I never lost a fish. They swam, they ate just fine.

That's when I found out the nitrates are not that poisonous to adult fishes.

Long story short, I got them down to around 160 ppm and waited 6 weeks as a test and still nothing happened to the fish. Now I just keep them under 80 ppm so algae is not a problem.

 

[Caliban07]

I think this is very true. I had my 75 gallon tank suffering from old tank syndrome with 20-25 African Cichlids three years ago. Water changes every 6+ months, added water only when evaporation occurred. I decided to get the tank straight and tested and found my nitrates at the over 160 ppm mark. So I changed 70% water and tested again. Still over 160 ppm! This means nitrates had to be over 300 ppm for a long time. Well I decided to find out why I never lost a fish. They swam, they ate just fine.

That's when I found out the nitrates are not that poisonous to adult fishes.

Long story short, I got them down to around 160 ppm and waited 6 weeks as a test and still nothing happened to the fish. Now I just keep them under 80 ppm so algae is not a problem.

My issue with high nitrates is that these are usually the smoking gun from a high turn over of ammonia. High turnover of nitrification means a higher turnover of oxygen and a greater biological oxygen demand. It is in these persistent low oxygen environments that things can start to get a little wonky.

 

[fishwonder]

My issue with high nitrates is that these are usually the smoking gun from a high turn over of ammonia. High turnover of nitrification means a higher turnover of oxygen and a greater biological oxygen demand. It is in these persistent low oxygen environments that things can start to get a little wonky.

Well just to let you know, all during my 'issue' above, I never had any ammonia at all, zero. Yes, I tested for that because I thought the same thing, but nothing.