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Hi there!
This is my first time posting on this forum, so please tell me if I'm in the wrong place. This is also a long post - bear with me! I want to really understand what's going on here, so please comment on and critique my thought processes and assumptions.
I work at a hobby farm doing animal care, and they recently started up a koi pond. I've worked professionally with aquatic systems before but only in tanks (saltwater and freshwater, laboratory research and educational displays - up to 2k gallons), so I'm adjusting to the less controlled settings of a pond! I'd really appreciate feedback on my thought process and what is going on here, as well as any advice/suggestions. In places where I'm estimating, it's because I'm not the owner, so I don't always know *exactly* when something was purchased or what it was. I only started helping in pond care recently because more attention has been focused on turning this into a koi pond.
Pond specs:
-Estimating 2.5k gallons
-Pump circulates through to a waterfall
-Filtration = skimmer basket and a filter pad below that/right above the pump. I've been rinsing them weekly, decent amount of muck in the filter pad but not really more than I'd expect. No other filtration, and the line from the pump to the waterfall is buried with no access points that I'm aware of, so I think it'd be hard to add something in-line like a UV filter :/
-Pond is in full sun and we are in Colorado (front range) so it's FULL sun, we have very few cloudy days
-Pond has been running for about a year
-6-8 small koi and goldfish (3-4 inches), 1 6in koi, 1 12in koi. 6 of the small fish were added several months ago, the 6in koi and a few more small fish were added maybe 3 or 4 weeks ago, and the 12in koi was added about a week ago. A few of the small fish have been found dead in the skimmer basket over the past few weeks. Maybe 2 or 3 total.
-We've added some pond plants, all have been in for at least a couple weeks now. 7 1-gallon pots (water lilies, some generic reeds, iris) and 2 1/2-gallon pots (horsetails)
All chemistry is from API kits (the liquid indicators, *not* the strips)
Chemistry from a week ago (tested the same 2 weeks ago too)
Ammonia: 0
Nitrite: 0
Nitrate: 0
Phospates: 0.25
pH: 7 in morning, maxing out (wide-range pH reads up to 9) in afternoon)
KH: 60ppm
Some foam around skimmer and in the basket
Interpretation: I feel like I *always* see at least some nitrates in tank systems, but the lack of nitrates here didn't really worry me, the pond has been going long enough and had fish in it long enough that I'm pretty confident it's cycled (plus no ammonia reading). There was a decent bit of algae growth (probably where the nitrates are going) which made sense with the phosphate reading plus the warming season and sunny weather. The wild pH swing was very concerning - assuming that is due to high algae load and lots of photosynthesis pulling out lots of CO2 during the day plus the really low KH not being able to buffer the pH.
Actions: made sure feeding was kept minimal. My employer bought a pH stabilizer from the local koi store (this product) and we dosed according to instructions. Also treated with a pond clarifier - I can't remember the specific product, it was one they already had so I figured I would use it up first. Generic "beneficial bacteria to help clear up pond scum" type thing. Tested the KH a few days later and it had gone up to 100ppm.
Chemistry from yesterday:
Ammonia: 0.25ppm
Nitrite: 0.25ppm
Nitrate: 20ppm
Phosphates: maxing out the test IMMEDIATELY (test reads to 10ppm), not needing any time to develop. So somewhere well above 10
pH: 7.5 in morning, 8.5 in afternoon
KH: didn't have opportunity to test
Foam mostly gone, really only inside the skimmer basket
Other factors - it's been really hot here lately, we're hitting 95-100 degrees most days. Sun beating down. There's also a tree nearby that flowered and has been dropping it's little flowers like crazy the last couple days (pretty sure it's a honey locust - small green flowers) I scooped a ton out of the skimmer box.
Interpretation: This has me a little freaked out. I'm used to treating nitrites as a HUGE red flag, immediate large water changes, etc. but I feel like I'm reading conflicting info about nitrites from resources about ponds - some people seem to have that "yikes" reaction and others seem like "meh, as long as they're below 0.5". All the nitrogen products seems to indicate a big addition of organic matter and/or fewer nitrogen products are being consumed. Nitrogen cycle is clealry still functioning so thank god for that. The nitrates are a comfy level, I'd prefer the ammonia to be 0 but 0.25 isn't panicking me, but the nitrites worry me.
And holy phosphates. I tested the hose water right away, it's reading at 0. Asked the owner about fertilizer applications in the area (there's some planted flowers around the pond) and he said there hasn't been any. So - presumably being produced internally. Similar to nitrates, either a lot more organic matter breaking down, and/or less is being consumed.
At least the pH is starting to stablize... but still not where we want to be.
Fish all still active, the big one likes to hang out in the deepest part near the bottom - not sure how normal that is. No one gasping or surface breathing.
Here's my hypotheses:
1. A lot of the algae has started dying off and decomposing. I feel like the algae has changed and looks more scummy than before, but I'm not used to looking at pond algae (sounds dumb to say that but please don't judge lol). Less consumption of nitrates + phosphates, and more production of nitrogen products and phosphates as it breaks down
2. All those itty bitty flowers falling in the water starting to breakdown - adding nitrogen products and phosphates
3. The heat is speeding up decompisition things are breaking down faster than they can be consumed.
4. All of the above?
Actions:
They don't own a pond vacuum. I did what water change I could, conscripting an industrial vacuum/mopper they have (it's a Waxie Versa, felt sort of ridiculous lol but it works. No chemicals on it, don't worry) which wasn't ideal but it allowed me to change probably a few hundred gallons. Sucked up algae and debris where I could but there's lots more left. That was all I had time for.
Feedback I'm hoping for:
-Are my thoughts and assumptions on the right track? Are there places where I could improve or correct my understanding?
-How worried should I be about the nitrite and phosphate spikes?
-What's the best path forward for bringing the nitrite and phosphate down?
-Anything else I should be doing to stabilize pH?
-Any other general advice on this setup?
I've attached several photos. I'm not sure if you can see the file names which have the dates in them... General pond photos from about a month ago, the pond from a week ago when the newest fish (the 12in koi) was added and where it's got some foam, and the scum/algae from yesterday as well as those little flowers that fell everywhere.
Thank you so much for taking the time to read and respond!
This is my first time posting on this forum, so please tell me if I'm in the wrong place. This is also a long post - bear with me! I want to really understand what's going on here, so please comment on and critique my thought processes and assumptions.
I work at a hobby farm doing animal care, and they recently started up a koi pond. I've worked professionally with aquatic systems before but only in tanks (saltwater and freshwater, laboratory research and educational displays - up to 2k gallons), so I'm adjusting to the less controlled settings of a pond! I'd really appreciate feedback on my thought process and what is going on here, as well as any advice/suggestions. In places where I'm estimating, it's because I'm not the owner, so I don't always know *exactly* when something was purchased or what it was. I only started helping in pond care recently because more attention has been focused on turning this into a koi pond.
Pond specs:
-Estimating 2.5k gallons
-Pump circulates through to a waterfall
-Filtration = skimmer basket and a filter pad below that/right above the pump. I've been rinsing them weekly, decent amount of muck in the filter pad but not really more than I'd expect. No other filtration, and the line from the pump to the waterfall is buried with no access points that I'm aware of, so I think it'd be hard to add something in-line like a UV filter :/
-Pond is in full sun and we are in Colorado (front range) so it's FULL sun, we have very few cloudy days
-Pond has been running for about a year
-6-8 small koi and goldfish (3-4 inches), 1 6in koi, 1 12in koi. 6 of the small fish were added several months ago, the 6in koi and a few more small fish were added maybe 3 or 4 weeks ago, and the 12in koi was added about a week ago. A few of the small fish have been found dead in the skimmer basket over the past few weeks. Maybe 2 or 3 total.
-We've added some pond plants, all have been in for at least a couple weeks now. 7 1-gallon pots (water lilies, some generic reeds, iris) and 2 1/2-gallon pots (horsetails)
All chemistry is from API kits (the liquid indicators, *not* the strips)
Chemistry from a week ago (tested the same 2 weeks ago too)
Ammonia: 0
Nitrite: 0
Nitrate: 0
Phospates: 0.25
pH: 7 in morning, maxing out (wide-range pH reads up to 9) in afternoon)
KH: 60ppm
Some foam around skimmer and in the basket
Interpretation: I feel like I *always* see at least some nitrates in tank systems, but the lack of nitrates here didn't really worry me, the pond has been going long enough and had fish in it long enough that I'm pretty confident it's cycled (plus no ammonia reading). There was a decent bit of algae growth (probably where the nitrates are going) which made sense with the phosphate reading plus the warming season and sunny weather. The wild pH swing was very concerning - assuming that is due to high algae load and lots of photosynthesis pulling out lots of CO2 during the day plus the really low KH not being able to buffer the pH.
Actions: made sure feeding was kept minimal. My employer bought a pH stabilizer from the local koi store (this product) and we dosed according to instructions. Also treated with a pond clarifier - I can't remember the specific product, it was one they already had so I figured I would use it up first. Generic "beneficial bacteria to help clear up pond scum" type thing. Tested the KH a few days later and it had gone up to 100ppm.
Chemistry from yesterday:
Ammonia: 0.25ppm
Nitrite: 0.25ppm
Nitrate: 20ppm
Phosphates: maxing out the test IMMEDIATELY (test reads to 10ppm), not needing any time to develop. So somewhere well above 10
pH: 7.5 in morning, 8.5 in afternoon
KH: didn't have opportunity to test
Foam mostly gone, really only inside the skimmer basket
Other factors - it's been really hot here lately, we're hitting 95-100 degrees most days. Sun beating down. There's also a tree nearby that flowered and has been dropping it's little flowers like crazy the last couple days (pretty sure it's a honey locust - small green flowers) I scooped a ton out of the skimmer box.
Interpretation: This has me a little freaked out. I'm used to treating nitrites as a HUGE red flag, immediate large water changes, etc. but I feel like I'm reading conflicting info about nitrites from resources about ponds - some people seem to have that "yikes" reaction and others seem like "meh, as long as they're below 0.5". All the nitrogen products seems to indicate a big addition of organic matter and/or fewer nitrogen products are being consumed. Nitrogen cycle is clealry still functioning so thank god for that. The nitrates are a comfy level, I'd prefer the ammonia to be 0 but 0.25 isn't panicking me, but the nitrites worry me.
And holy phosphates. I tested the hose water right away, it's reading at 0. Asked the owner about fertilizer applications in the area (there's some planted flowers around the pond) and he said there hasn't been any. So - presumably being produced internally. Similar to nitrates, either a lot more organic matter breaking down, and/or less is being consumed.
At least the pH is starting to stablize... but still not where we want to be.
Fish all still active, the big one likes to hang out in the deepest part near the bottom - not sure how normal that is. No one gasping or surface breathing.
Here's my hypotheses:
1. A lot of the algae has started dying off and decomposing. I feel like the algae has changed and looks more scummy than before, but I'm not used to looking at pond algae (sounds dumb to say that but please don't judge lol). Less consumption of nitrates + phosphates, and more production of nitrogen products and phosphates as it breaks down
2. All those itty bitty flowers falling in the water starting to breakdown - adding nitrogen products and phosphates
3. The heat is speeding up decompisition things are breaking down faster than they can be consumed.
4. All of the above?
Actions:
They don't own a pond vacuum. I did what water change I could, conscripting an industrial vacuum/mopper they have (it's a Waxie Versa, felt sort of ridiculous lol but it works. No chemicals on it, don't worry) which wasn't ideal but it allowed me to change probably a few hundred gallons. Sucked up algae and debris where I could but there's lots more left. That was all I had time for.
Feedback I'm hoping for:
-Are my thoughts and assumptions on the right track? Are there places where I could improve or correct my understanding?
-How worried should I be about the nitrite and phosphate spikes?
-What's the best path forward for bringing the nitrite and phosphate down?
-Anything else I should be doing to stabilize pH?
-Any other general advice on this setup?
I've attached several photos. I'm not sure if you can see the file names which have the dates in them... General pond photos from about a month ago, the pond from a week ago when the newest fish (the 12in koi) was added and where it's got some foam, and the scum/algae from yesterday as well as those little flowers that fell everywhere.
Thank you so much for taking the time to read and respond!
