Nitrite levels high after pond clean

[broniem]

Morning everyone,
I'm really hopeful someone can help. I have a approx. 2200lt pond with about 15 goldfish (started with 6 just 6 months ago). The pond was starting to look a bit murky so I did a big clean and water change yesterday. I probably did a 25% water change with rain water from our rainwater tank (no tap water) and vacuumed up a bit of sludge from the pebble bottom. I cleaned out the sponges in the filter, which were quite full of algae and I only used pond water for this.

The pond is looking good this morning but I've done a water test using Oase Quickstick test this morning and the Nitrite levels are high, Nitrate is OK. I've tested the rain water in the tank and the Nitrite levels in the rainwater tank are OK. These Quicksticks are not great and I need to get a better test kit but I've not seen the Nitrites this high before, not even when I was starting up the pond 6 months ago.

My fishy family (I know they are only goldfish) all seem to be OK at this point but I am concerned. Could the spike in Nitrites be because I stirred up the pond cleaning it yesterday?

The Ph is also only 6.8.

 

[Mmathis]

Hello and welcome!

What WAS the nitrite level and what were your water parameters BEFORE you did the clean-out? Optically clean water isn’t necessarily healthy water, and vice verse. My guess is that you did upset your pond’s equilibrium / biofilter — a rookie mistake. You have a decent bio load for your pond’s size, and it’s more important to monitor your water testing when you have a smaller volume of water.

Tell us what your test results are (actual numbers, not “ok” or “normal”), and from there we can advise.

What does you pH normally run, and do you have a test kit for KH (carbonate hardness)? Again, more information needed before we start throwing solutions at you.

As a general rule, we recommend using a liquid, dropper-style test kit. Strips tend to be less reliable.

 

[broniem]

Yes, unfortunately the strips do not provide detailed measurements. For Nitrite levels its only either good or bad, (coloured or not coloured.) Prior to the cleanout the Nitrite levels were good i.e. no colour indicated on the strip.

I understand that the pH, at 6.8, is a bit on the lower side than is optimal but I find it really hard to keep the pH higher than this. I am on the Gold Coast in Queensland Australia and we have had a tremendous amount of rain which doesn't help. Hardness is also essentially non-existent. I can add some bi carb to the water but I didn't want to do this in case it made the Nitrite situation worse.

I won't be able to get a decent test kit until tomorrow.

Is there anyway to tell if my fishies are distressed or suffering because if this .

 

[brokensword]

"Hardness is almost non-existent"

A KH test is what you want and as you already guess, hardness is a factor here. I have no doubt your pH dropped as rainwater is typically acidic. The KH of your pond being sufficient is key to keeping pH changes/crashes in check. A liquid test is better than the strips. Real numbers a much better view on what's going on. I'd slowly start adding the bicarbonate so the pH both rises and your water attains the ability to weather such changes. You can add crushed egg/oyster shells or crushed coral and get better/more long term stability.

A good thing at the moment is that ammonia isn't dangerous in acidic conditons, so one less worry. The nitrites should be converted by the good bacteria, once they re-colonize. Don't feed for a bit, it'll help (the fish will feed on algae, plants, etc). Don't worry about any green water for a bt as the algae will actually help clean the water. Once stabilized, putting more plants in will outcompete the algae and that'll clear, plus help filter better. Floaters are better at this than the marginals, though some iris are also great for this.

New test kit, monitor, get yourself some (bags) of crushed egg/oyster/shells or coral and give it some time. Again, SLOW upping of the pH and you don't need that much pH change as you need to insure sufficent alkalinity/mineral in the water.

 

[broniem]

Thanks very much for that @brokensword. I have got some crushed coral in a bag in the waterfall already and I will definitely be getting a better test kit as soon as I can. I've put some bicarb in (just a cup mixed with pond water in a bucket and added) and will test again daily over the next few days.

I really didn't think I'd knocked out that many beneficial bacteria when I did my clean, it wasn't like I emptied the pond and scrubbed it. And I never use tap water to clean or fill. I will just have to hope that my hardy little goldies will survive the next week while, fingers crossed, it gets back into balance. Note to self - smaller more frequent water changes.

 

[brokensword]

Thanks very much for that @brokensword. I have got some crushed coral in a bag in the waterfall already and I will definitely be getting a better test kit as soon as I can. I've put some bicarb in (just a cup mixed with pond water in a bucket and added) and will test again daily over the next few days.

I really didn't think I'd knocked out that many beneficial bacteria when I did my clean, it wasn't like I emptied the pond and scrubbed it. And I never use tap water to clean or fill. I will just have to hope that my hardy little goldies will survive the next week while, fingers crossed, it gets back into balance. Note to self - smaller more frequent water changes.

realize, I'm talking like 50lb bags; you're going to need a lot, sort of like you might if you've ever kept saltwater fish. And it'll take time for your current water to transform but it'll work. I believe @addy1 did this to her pond, so she can chime in and give you further details as her pond started out in the range of pH 5.

Also, it isn't the water changes as I'm not a proponent of ANY water changes. I've only ever topped my pond off due to evaporation. If you have a balanced system, that's the goal. Hose topping off and rain topoffs are all you should need. And you didn't do THAT large a change; it seems okay if you're trying to majorly help the fish due to some chem you put in and can't dilute any other way; that isn' the issue. I believe it's your low KH and the rain water addition. So, no, take that note to self and tear it up...

If rainwater IS your main topoff source, you're going to have these issues, hence building up the KH will keep you in the pond busines longer. I'd do some tests on it and/or your tap water if you use that, to see where you're starting from and what kind of water you're putting in as replacement.

 

[WaterGardener]

I think it is more likely that the rain caused the problem, not cleaning the pond. I doubt cleaning it would have affected the bacteria that much. Acidic rain could have.

Yes, please add the baking soda and get the alkalinity (KH) and pH up where it needs to be. KH can be depleted with the nitrogen cycle, which produces acid, so it's normal for it to fall. It needs to be monitored from time to time and boosted when the numbers start to lower.

Prime will bind the nitrite, as well as ammonia, and it will keep the fish safe. For that purpose it will last only 48 hours so it would need to be dosed again after that time. It could be helpful until your system gets stabilized again.

 

[Lisak1]

Whenever someone mentions acid rain I always remember Meyer Jordan saying "all rain is acid". He once posted a mathematical formula to prove that even a heavy rainfall only adds a small percentage of water to a pond, so even if it is acidic (or I think he may have been discussing contamination from rainfall in that thread) the likelihood that it would affect the pond to any degree was very small. (Clearly the details allude me, but I do remember his overall point!) I'll see if I can find the post.

 

[Lisak1]

Here it is!

Do u think nitrates level and nitic acid rain has relation to yearly rain percipitation , level can b less where rain fall is high and other factors can contribute aswell , emission of gases , pollution etc bcz he lives in rajistan its desert most of it.

ihv noticed similer behaviour here when it rained after long gap the fishes show very bad symptoms all would come on surface gasping for air ,eithor could be mixing of carbondioxide in warmer places as rain is cooler whats your research on it.

Rainfall can contain many different pollutants depending on geographical location, but as to how it may affect a garden pond simple math is all that is involved.
A garden pond properly constructed will not suffer any contamination from run-off due to irrigation or rainfall. This leaves only the surface area of the pond to collect rainfall. The amount of rainfall collected by this surface area in gallons is a very low percentage of the pond's total capacity. Example: A Pond is 10' x 10' x 2' deep, vertical sides. Capacity in gallons is 1496 gallons. This pond is exposed to 1 inch of rainfall. The amount of rain (in gallons) is 100 sq.ft. x 0.083 (1/12th of an inch) = 8.3 cubic feet or 62 gallons. This 62 gallons then needs to be added to the existing pond capacity- 1496 + 62 = 1558 gallons. So the rainfall percentage of the total pond capacity is 62/1558 or about 4%. Since the pollutants contained in the rainfall will always be considerable less than 100% this means that considerably less than 4% pollution is added to a pond with a 1 inch rainfall event. To truly affect the balance of a pond rainfall would need to 1. Be falling at a quite heavy rate, 2. Be continuous for several hours or days, 3. Contain quite high levels of a known pollutant(s).
Usually the temperature of the rainfall will be the source of any occurring issues.

 

[BKHpondcritters]

OK, math is not my strong suit, but why is the amount of rain calculated at 100 square feet X 1/12 of an inch? Didn't the entire inch of rain fall on the entire 100 square feet of surface area?

And, math aside, all I know is that rain absolutely effects my pond, specifically in dropping the KH. Now I do have a LOT of surface area, more so than depth, as well as a significant amount of area in the 'upper pool' which does not hold water, but adds it all down into the main body of the pond. My pond's level rises way more than what simply is measured in fallen rain.

 

[Lisak1]

math is not my strong suit,

Same. I just know Meyer was a smart guy who knew what he was talking about.

 

[BKHpondcritters]

OK, I went googling & found an easier way to get the same/right answer. 1" of rain = .623 gallons per square foot. So, yes, a 100 square foot pond would gain approx. 62 gallons with a 1" rain.

I'm now very curious exactly how many square feet of surface area my pond has. Might have to bust out the tape measure & do some calculating.

 

[j.w]

@broniem

 

[WaterGardener]

I know for certain that rainfall affects the KH in my pond. I test for KH and I can see that it will fall after a heavy rain.

That's an interesting article, but it addresses pollutants, not rain. I'm not sure what he means by that. I also think there are other factors involved that are not considered.

It's not just the volume of pond water that is significant. The surface area plays a major role. If you have 2 ponds each holding 1500 gallons of water, one pond 4 feet deep and one pond 1 foot deep, the shallower pond is going to gather a lot more rainfall than the deep one. That pond would have a larger surface area and would be more affected by the rain.

Rain has a pH of 5.6. Acid rain has a pH of 4. It drops in pH from being exposed to exhaust from cars, smoke from fires or manufacturing plants, and other types of air pollution.

And although all the rain may not contain the pollutants mentioned in the article, whatever those may be, all of the rain will be acidic, 100% of it, not some portion of it.

I would think that smaller ponds would be more affected than larger ponds. My feeling is that they would be more shallow and have a larger proportion of surface area than larger, deeper ponds. Could easily be wrong there, of course.

Also, if you have a bog, the bog is also collecting acid rain, so you have to include that in with the gallons of water and its large surface area and add that to the volume and surface area of the pond.

Depending on the pH of your pond water, one rainfall event of 1 inch may not have a castastrophic effect on your pond, but it will lower the pH, if only a little. But if you do nothing to buffer that acid, over time with subsequent rain, the pH will continue to drop.

Let's consider the rain and that 10X10 pond, and the 4% of the pond's water being acidic. Every subsequent 1 inch of rainfall would add another 4% of acid rain.

We get an average of over 38 inches of rain per year and 18 inches of snow. But just using the rain amount, that would be a total of 152% of that pond water, 38X4. So by the end of the year, if none of the water were removed, or evaporated, all of the water would be acidic, and that pond would have a pH of 4.0.

Okay, now it's your turn to blow holes in my theory.

 

[WaterGardener]

With further thought, that last bit may not be correct. The pond volume would be increasing with each rainfall, so the amount of increase in acidity might be slightly less than the 4%. The pH would still fall with additional rain, but not as much.

Also, in the real world, the pond would have to have some water removed or it would over flow. Some water will evaporate. The water remaining would still have a lower pH than in it had originally and would keep falling with more rainfall.

All in all, I think this is much more complicated than it seems.