Nitrite levels high after pond clean

[BKHpondcritters]

I'm going to do a hearty agree with your statement "I think this is much more complicated than it seems." I also think that each pond being an individualized, self-contained ecosystem, means that natural changes & effects brought on by rain (or pretty much whatever) varies greatly from one to the next.

I have seen the exact same KH changes in my pond brought about by a heavy rain (or accumulated rains) that WaterGardener has spoken of. Others on this forum report that their KH never changes for any reason. I think that's why it's so important to learn as much as you can about a wide variety of ponds & their set ups, then selectively apply what makes sense & works best for your own individual pond.

 

[WaterGardener]

Understatement of the year!

 

[WaterGardener]

That last part of post #14 is definitely wrong.

Let's try it this way. The rain water added to that pond would be 2356 gallons, the 152% increase, 62X38 inches of rain for the year, much more than double the amount of water in the original pond. Still working on the assumption that no water would be removed.

So, more than half the original volume has been added that has a pH of 4.0. I would think that would have a pretty significant affect on the pH of the total pond volume, no matter where it started, and would drop it into the acidic range.

Someone smarter and more ambitious than I am can figure out the exact pH, but I think I'm done.

 

[Lisak1]

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

I think you already did!

My brain isn't built for math, so I won't argue any numbers, but I would say when you're getting a heavy enough rainfall that your pond is overflowing, you're losing as much rainwater as you are pond water. Perhaps even more, since the pond will only hold so much water. Once it's full, I'd assume the majority of the overflow is rainwater. If I have an open rain barrel that's mostly full and the rain keeps falling I wouldn't assume it's a mix of old water and new rainwater that's overflowing. You can't add more water to an already full pond.

 

[WaterGardener]

That scenario wasn't real world and assumed there was unlimited space for the additional water. Just a hypothesis, not reality.

In reality, we pump out excess water when we get too much rain, so that has already mixed with the existing pond water.

Anyway, good thoughts on overflow. I have no idea if that might be true, but it seems reasonable enough.

 

[BKHpondcritters]

I think it depends on what type of hypothetical overflow system you have in your hypothetical pond.

Seriously, though - If your pond overflow is the type that depends on a low edge & the excess water floods out at the same rate the rain is falling in/filling it up then I'd assume that the majority of the overflow would be the rain water which would be on the top until more thoroughly mixed in via normal pump circulation.

However, if your set up is like mine (overflow pipe in the skimmer) I'd think that it's a more mixed water, old + new, leaving the pond. My pumps are pulling water in & sending it to the waterfalls (which do the mixing) at a much greater rate than what's being diverted out of the system, so I would assume that the end result is a greater volume of the new rain water staying within the system. The exact percentages? I think that would be completely impossible to determine. (I also think I'm thinking about this WAY too much! lol)

 

[WaterGardener]

Agitation from air discs in the pond would also be a factor in how quickly the rain would mix in, I would think.

 

[brokensword]

I think you already did!

Once it's full, I'd assume the majority of the overflow is rainwater. If I have an open rain barrel that's mostly full and the rain keeps falling I wouldn't assume it's a mix of old water and new rainwater that's overflowing. You can't add more water to an already full pond.

ah, no; the rain WILL mix with the pond water as it falls (there is no barrier between old and new, and this happens on a molecular level; think osmosis where concentrations/temps migrate to balance out; same will happen with new water added to old.) and you'll get a new pH (among other params) based on whatever is in the rain.

So if acidic, and pond is alkaline (pH >7), the pond is getting more acidic. As the rain adds to the volume and mixes, the total carbonates, hardness, etc is lessening due to the acid being added. If KH is high enough, a pH crash won't happen. If low, then yes, could be a problem. I think as Meyer noted; takes a lot of heavy rain to affect a pond that much unless you have a very shallow or low gallonage pond. As typical, a larger pond is easier to keep in balance once there and has more latitude for issues and time to fix. Do note, each .1 lowering of pH is a 1/10th decrease. The fish can adapt if it's a slow process, in either direction.

 

[SarahT]

So, Broniem, how are your fishies doing? Goldfish are pretty hardy, so I'd think they're ok.