Nitrate vs nitrite

[NancyMc]

I am asking this question because I just tested my water and I have a slight increase in nitrate but nitrite is negative. I am using strips. I did do a bit of reading online but did not come up with a satisfactory answer. I am using API test strips and the nitrate was 40-80ppm. I am not able to have plants in my pond because of the type and location of the pond...AND the one plant I did put in the pond when I moved the koi from outside to inside pond was dug up in short-order!! I have read that overfeeding is the most common cause of increase in nitrates/nitrites.
Other parameters - pH 6m which is lower than it has been before, the GH and Kh are high but always have been. Also wondering about expire date for the test strips because mine say June, 2021 were there expiry date...but I always wonder whether they are good for significantly longer than the expiry date says!
However, I think my biggest question is what the difference is between nitrites and nitrates? My research indicated that nitrates break down to nitrates but if I don't have a positive test for nitrites, why do I have nitrates? I did a water change two days ago before I tested my water so maybe it was even a higher reading before I did that. I replaced approximately 1/3 of the water and added chlorine neutralizer. Should I be removing/examining/cleaning my biofilter? I feel like I have enough water circulation with the pump that I have for the size of pond and number of fish but perhaps not. The fish appear to be eating well. No signs of toxicity.

 

[brokensword]

basics; nitrate is a lot less toxic (over time, the build of concentration) than nitrites. Plants ARE what you want to help take out the nitrates, or you'll have algae doing it for you. I'd really figure something out so you can have plants, be they potted and fenced IN the pond, or floating and protected by a net of some sort, or even better, in a bog filter attached to your pond.

Btw, use the liquid tests as the strips have been known to be inaccurate, and by a lot. API is a good brand, though.

Nitrates are the result of breaking down nitrites, which is a result of breaking down ammonia. In general (though not wholly accurate), bacteria are in charge of this process.


Not necessary to do water changes if your pond is in equilibrium. IF you clean your biofilter, use only pond water, NOT chlorinated water. A bog filter IS a biofilter and would solve a couple problems for you.

Do some regular pH checks as ph of 6 is on the acid side and imo, should be over 7 and in the basic spectrum. BUT, a steady pH is better than trying to find some magic number. I only mention because it might indicate your source water is acidic and will only give you more acidic readings going forward. Check your KH and see how that stacks up; this is an indicator of how well you can maintain your pH and if low, could also be giving you issues with other parameters.

Glad your fish are doing fine!

 

[WaterGardener]

Testing strips are not accurate. That makes them pretty useless. They start to deteriorate as soon as air hits them when the container is opened. Since yours are out of date, that adds to the problem.

I wouldn't trust any results you have from those strips. Get some liquid tests for pH, KH, ammonia, nitrite and nitrate. You will have a much better idea of your pond's water quality with those.

 

[NancyMc]

I have ordered an API test kit for accurate results. Not sure I can get any pond plants at this time of year but will call my aquarium shop and see what he has available. I have also started feeding less because the pond location is quite cool and maybe they are eating less than I thought they should be. I have also ordered another pump/bio filter. Sadly, no way to set up a bog filter in this pond. Will follow up in a few weeks when I have further information.
As always, thank you for your help.

 

[NancyMc]

Me again! I have been doing weekly water quality testing now for a month. I have increased my filtration and started my testing the week after I did that. My parameters have not changed much since then, except for the pH. It is getting more acidic over time and I don't know why! I cannot get any plants at any of my stores locally (that will be a project for next next year now). I have decreased the amount fed significantly and the fish are growing like weeds - active and eating well. My husband hadn't looked at them for a few weeks and he said the other day he couldn't believe how much they have grown! Anyways, perhaps this means that I should be less concerned about my parameters? However, the pH does concern me. What do you think?

 

[WaterGardener]

This is perfectly normal. The nitrogen cycle produces acid and uses up the alkalinity in the system that buffers the acid. Your pH is getting very low and you need to boost that alkalinity to keep it from crashing and killing your beneficial bacteria and your fish.

Do you have a KH test? That would tell you the level of the alkalinity, which I suspect is very low. I keep mine around 200 ppm, since that is where my filters work best. Anything over 100 is okay.

You can boost that with ordinary baking soda. I don't know how large your pond is, but you don't want to use so much that your pH jumps all at once. It needs to be raised gradually, over days, not hours.

The pH in my pond stays around 8.2 or 8.3 and I check the KH every now and then to see if it needs a boost. It's an ongoing process so it needs to be monitored.

 

[NancyMc]

Okay. Thank you. Do have an estimate for how how much baking soda per 10 gallons of water to start with? I did a Google search and it said 1tsp/10 gallons but that seems like a lot. I do not have KH test kit. Sadly, I didn't know I needed one. Would it be acceptable to simply test the pH instead of alkalinity?

 

[WaterGardener]

How large is the pond? How many gallons?

It can take quite a bit depending on the size of the pond. I use about 8 cups of baking soda for my pond which is 6,000 gallons. And that is just to keep it at the same pH level, not to increase it.

I recommend you get a KH liquid testing kit. I consider it the most important thing to test for.

 

[NancyMc]

My pond is small, which is why I think I am having difficulty - 130 gallons. I will invest in a KH liquid test kit.

 

[WaterGardener]

Once you get your KH kit and test the water, you can use this calculator to see how much baking soda you need to add,

Koiphen.com - Koiphen's Koi Calculators

As the largest Koi and pond community on the internet, the forum provides help and advice on pond building as well as Japanese Koi and Goldfish care including disease prevention and treatment.

www.koiphen.com

Or, you can start with the 1 tsp per 10 gallons and keep a close eye on the pH. Do one dose per day until the pH is at a good level. If you get it around 8.2, there should be plenty of alkalinity in the system to keep the pH stable at that level.

Raising the pH will also help with the nitrogen cycle and you will likely see an improvement in the water parameters.

 

[NancyMc]

Just ordered the KH kit and will arrive tomorrow. Thank you Amazon Prime!!

 

[WaterGardener]

Best of luck with your pond.

 

[NancyMc]

So...I got my kit and tested the KH/alkalinity. The results were:
dKH- 4.1
The formula I found converts dKH to alkalinity in mg/L by multiplying by 17.9 = 73.4mg/L
I understand that this is too low and that I want to increase that by adding baking soda, then measure again...perhaps later in the day?

 

[WaterGardener]

It took 4 drops to change the color in the tube?

If you have the API test kit here is a chart in the instructions that come with the kit.

You are correct with your numbers and your plan sounds good. Add a small amount of baking soda and see how much of a change that makes. Don't try to raise it all at once and shock the fish.

Depending on how you use the calculator link, it can show you how much total baking soda you need to get to your goal. Just break that amount up into smaller portions to use each day until you get to the desired level.

 

[NancyMc]

The kit I purchased is actually "Salifert", made in Holland, so probably different formulation than the API kit. it was the one I could get the quickest. I do have a scientific brain - majored in chemistry in university and am a retired veterinarian, so am enjoying straining my brain on this KH vs GH vs Alkalinity vs pH!! It is something I haven't had to think about for years. So thank you for answering all of my questions and I will start to adjust the alkalinity. One more question (and probably not my last!!) - at what point do I measure the pH? Should I be adjusting the alkalinity "as required" and not be worrying so much about the pH... or is it a combination of the two?