Yesterday I hauled several gallons of intact/non-decomposed maple leaves from my 8 x 12 pond (the pond was built beneath a tree - not by us; and it released about half its leaves in a two-day period.) They weren't in there long enough to begin decaying, so I was feeling pretty good the pond is just about ready for winter.
In the upper biofilter/waterfall, there was a lot of really nasty, dark/black "clots" of slime in the pea gravel. It was pretty strong stuff (but not fibrous). When I picked up the clumps, they would release the rocks but stay in one piece. Sorry for the gross description, but this stuff resembled big (quarter-size to fist-size) dark-colored blood clots - very slimy and nasty (but not noticeably foul-smelling; at least nothing worse than the usual pond smell when I have to clean that many leaves from it.)
I did what I could to get rid of all that gunk, and this morning I found it was completely blocking the hose and tubing that runs into the bio filter, so that got completely cleaned out too (outside the pond, so I don't think there's much of this stuff in the pond itself.)
But after I got that done, I noticed all day that my fish were (and are) staying near the surface for oxygen, which worries me - they've never done this before. The waterfall is still working, so the pond is receiving the same amount of oxygen it did all summer, when they acted normal.
Is there something in the water that is causing a major anaerobic effect? Is it related to this gunk? (I've never seen anything like it before - a few bouts of string algae is about the worst problem I've had to contend with in the past four years.)
And most importantly, what can I do for my fish? Help, please!!!!
Nasty slime & fish are staying near top of water - help!
Are you able to get any supplemental aeration into the pond right now? Do you have any indoor aquariums that you could borrow a few air pumps and air stones from to help your fish breathe a little easier? Do you have any spitters in any water features that you could temporarily relocate to your pond? Are there any stores open where you live where you could send your husband to run for a few whisper pumps, air hose, and air stones?
What size is your pond?
What is your fish load?
What type of a biofilter do you have?
What't the gph on your pump?
Do you have a UV filter for single cell algae?
You've had string algae before, did you get rid of it by using hydrogen peroxide?
What is your water testing at? What's your kh and ph?
Do you have a WalMart by you where you could pick up one of those kiddie pool vacuums to help get rid of some of the debris at the bottom without stirring it up?
Are you in a position to do a partial water change? Maybe remove the mulm and try at least a 25% water change? Then hold for a day and change 25% and then repeat in another two days. Load with 4x the recommended dose of Novaqua to reduce stress to your fish.
Terry, I haven't had this happen to me in years. I can't remember what caused it but I remember having to run out and buy anything I could get my hands on until I could start water changes. I also found that my kh had crashed.
Just out of curiosity do you use any type of an algaecide such as AlgaeFix right after winter is over to help nip some of the spring algae? Another product to consider might be a Microbe Lift to add bacteria at the same time to help eliminate dead algae and other organic debris. If you or any friends have indoor fresh water aquariums, you can squeeze out the foam prefilter and pretty much enjoy the same microbial benefits as if you had purchased bottle bacteria.
I feel horrible for you.
I remembered I had a 12" air stone after I posted this, so I've plugged it in and it's bubbling away - hopefully that will help, at least until I figure out the root cause.
What size is your pond?
Roughly 800 gallons
What is your fish load?
About a dozen of smaller fish (8" or smaller), give or take. All are goldfish or shubunkin (no koi)
What type of a biofilter do you have?
it's a fairly large pea gravel pit (3' x 3' x 18" deep) A pump (appropriately sized) pulls water from the pond into the farthest area, so the water filters through all the media before running back into the pond via a small watefall.
What't the gph on your pump? Offhand, I don't recall, but I do remember we made sure it was sized properly when we bought it.
Do you have a UV filter for single cell algae? No.
You've had string algae before, did you get rid of it by using hydrogen peroxide?
No - I used only hand removal. (lots and lots and lots of hand removal ;o)
What is your water testing at? What's your kh and ph?
Hanging my head - in four years, I've never tested the water (it stays pretty clear, except for spring "pea soup" algae that clears up with some AlgaeFix and/or MicrobeLift, and constant cleaning of the pump's filters. Tomorrow I'm heading to the pond store for test strips and then I'll see if I need pH up or down, and if there's a nitrate problem.
As to a partial water change, I added about 10% new water yesterday (the pond was a little low, so I added it while I was working on the filter and pump cleanings.)
Topping off the water can bring some immediate relief in the form of adding oxygen but it is not the same as doing water changes. That water that evaporated left behind concentrated bad stuff for lack of a better way to describe it. I'm thinking you are going to discover you have a nitrates issue compliments of the decomposing matter in the pond. Add to this all the heavy rains we've been getting and this too can become an issue. Rain is acidic. The rain throws off the kh and reduces the ph. The next little issue is the plants, they're going dormant right now and aren't producing as much oxygen as they did over the summer. Additionally, plants make oxygen during the day but they use it up at night so I'm glad you got your hands on an air stone and pump.
12 fish might be a tad high. The pump you have may have been fine when they were little guys but might not be adequate now that they've had the whole summer to grow. Tomorrow when it's daylight you might want to see if there is a rating on the pump. Your pump might not have enough oomph for your current fish load.
If you're picking up test kits, maybe you could pick one up for the kh? I have this little voice that says you might want to check that.
Last thing I can think of that might bring some relief, if you pick up one of those little kiddie pool vacs, you can do a partial water change at the same time you are removing some of the organic debris that is breaking down and adding to your issues. Terry, I think the one I bought at WalMart was under $20. Everybody seems to think they are a lot more expensive. I bought a back up kiddie pool vac from the clearance aisle at WalMart about this time last year for like $7 or $9. They are also quick and easy to use.
I can do a partial water change, but not until this weekend - hopefully by then, the fish won't be quite so traumatized. The good news this morning was that they're no longer gasping for breath at the surface, except for one first-year fish (about 2" long.)
The others are all swimming happily, many hanging out near the airstone. I really don't think there are too many fish - when I said 8", that's the biggest of them - most are in the 2" to 6" range. We try to keep around a dozen in there - we share some of babies with friends in the summer (easy to give them away when they turn up with the shubunkin coloring.)
The pump is rated for at least 1,000 gallon pond (we made sure it was larger than our best guesstimate as to the volume in this pond (it was hand-dug and irregularly shaped, so it's not easy to pinpoint its exact volume, but were pretty close.)
I'll definitely check WalMart for a kiddie pool pump (I've wanted a pond pump, but they're sooooo expensive I can't justify the expense. But for $20 or less, that's a no-brainer.)
And I'll definitely get some test strips and then choose a treatment plan after I see what the probable cause(s) are. I've never added salt to the pond, but I may add a couple pounds once I figure out if we need to add anything else to remedy the immediate problem, and do a partial water change.
BTW, the leaves weren't decayed at all - they had just left some tannins in the water, turning it pretty dark. (That's a very common occurrence each fall, and has never caused a problem up to now.) I still don't know what would have caused the slime - I'm reasonably sure nothing died in there and I know the bottom has very little debris at this point.
Hi There, the thingie I bought at WalMart was a vacuum not a pump. It attaches to your garden hose. It has a great little filter bag that can be emptied.
Salts work but you might want to look into that product called Novaqua-
http://www.elmersaquarium.com/h125novaqua.htm
I think you can get it at PetSmart or PetCo but I order mine on line in the gallon size.
Your biofilter pump at 1000gph should be ok I would think if it is still pushing water at that rate. Sometimes pumps get old. There are two members here who are seasoned veterans. One is named Oconus (sp?) and the other is named DRH with a number after his user name. Both are somewhere floating around, and both know mechanical, electrical, and pond chemistry pretty well. If after you start water changes, you are still having issues maybe a link to this thread could be sent to them. They're the two people I would run to for help.
I've seen thousand gallon ponds with fifteen 10-14" koi in them and the fish all seem healthy and nobody is gasping for air at the surface. Rule of thumb is 1 koi per 500 gallons but people are getting by with considerably less volume per fish quite successfully all the time. Sometimes no rhyme or reason.
The fish hanging by the air stone is an indicator there are oxygenation concerns but at least they're not hanging around at the surface any longer so a water change could definitely wait until the weekend.
I get the tannins in the water myself from leaf drop every single year. I've got mostly oak around here so I remove the leaves by just skimming them off the top whenever I walk by a pond. If I'm really motivated, I swish my hand around the bottom and pull up an oak leaf glob. Other than that, I vacuum at the same time I do water changes and that picks up organic debris. Tea stained water is not necessarily unhealthy, its just tea stained.
Sorry - yep, I meant vacuum but typed pump (not enough coffee coursing through my veins yet!) Thank you for all the advice - it's definitely reassuring! I wasn't too worried about the color of the water (other than I like to be able to see the bottom of the pond, especially when I'm getting in it to clean out leaves, lol.) But when the poor fish were all "sucking wind" at the top of the pond, I was immediately concerned.
The last time they did that was when DH improperly calculated the amount of Crystal-plex (a pond clarifier chemical he bought at Tractor Supply) and it killed them all. That was two or three summers ago, and we haven't had any problems with the replacement fish since. The slime is/was a new one on me, though.
Thanks for the tip - I'll check Petsmart (it's near our WM) for Novaqua; they've got a pretty good aquarium/pond section - that's where I bought the airstone last year, as I recall.
Terry,
Have you had a fairly quick drop in temp recently? Seems like I remember that the ponds in the Japanese gardens at the Birmingham Botanic Gardens would be pretty green and then overnight after a cool snap the water would be clear. The algae might be undergoing dieback, clumping in the bottom and decomposing.
Beth
Hi Terry,
I doubt the leaves are an issue but it’s good that you got them out of there. Given your location I suspect that your water temperature is in the low 60's maybe high 50's about now. The reason this is relevant is that it means that the water temperature is low enough so that it will hold sufficient oxygen.
It’s difficult to accurately diagnose what’s going on without being right there on the spot - sort of like trying to measure your pulse over a phone with the receiver held about a couple of inches away from your wrist!! :-)) So here’s what I think may have happened: those black clots that you found were probably accumulations of biomass on your filter/gravel bed. What happens is the microbes grow all over everything. However, as soon as the thickness begins to exceed even about 100 microns or so the layer in tight against the rock begins to turn anaerobic since the rate at which oxygen can make it through the biofilm becomes restricted. There’s nothing you can do to change that other than clean everything to keep the biofilm down. Normally this is not a problem since what will happen is that the outer layer of the film is aerobic with the inner layer being anaerobic or at least pretty close to being anaerobic. In most cases when this happens a small piece of the biofilm will sluff off the surface and then new “stuff” begins to grow in it’s place. Even when this remains in place it’s not much of a problem. The outer layer will convert ammonia nitrogen to nitrates and the anaerobic layer will take whatever nitrates it can get and convert them to nitrogen gas - totally harmless. In fact this is the practice of denitrification. The down side is that the anaerobic layer will also convert sulfates to hydrogen sulfide. Again, with the film in place this isn’t much of a problem since as the hydrogen sulfide diffuses out through the film it’s reoxidized to sulfates which don’t do too much. You say you didn’t smell too much of anything when you stirred up your biofilter/gravel bed. But what probably happened is that you released a very large amount of the anaerobic biomass into your pond. Even very low quantities of hydrogen sulfide can create the respiratory stress you observed. Plus the sudden loading of suspended microbes can cause a dip in oxygen levels.
It sounds as if your pond is coming back to an even keel at this point. When I clean my biofilters I take them off line so that no water is going through them. I do whatever I’m going to do including pumping all of the water out of the biofilter so that I’ve only got the media in there when I start it back up. That way I’m filling the biofilter back up with pond water but any dislodged solids don’t go back into the pond since I got rid of them when I pumped out the biofilter. A few solids won’t make much difference but if you released a large amount back into the pond that’s when things go “South” as they say. Did you observe that the water had a bit higher turbidity after you worked on the gravel bed? Even after I’ve worked on mine it’ll be a ‘tad bit higher turbidity for an hour or three but it’s usually clear within twenty-four hours.
Given, as I mentioned above, that the water temp is headed to cooler levels it should not be difficult to maintain adequate oxygen levels. If I’m doing a lot of work in the pond I’ll drop a 12" airstone in and bubble as much air in there as possible (use the largest air pump you can get at Petsmart or HD or wherever - something on the order of 4 - 5 liters/min free air capacity and only put the stone down about 1 to 1½ feet). Not only are you adding air but you’ll also be helping to strip out any bad gases such as hydrogen sulfide that might be released. Of course, as an alternative you could remove the fish for a day in wading pool (with aeration) while the pond re-establishes itself.
As Equilibrium has said, get yourself an alkalinity (KH) kit. Also get a nice, big, cheap box of baking soda. Nice stuff to add to your pond to stabilize the pH and increase the alkalinity in case you’ve also got pH swings compounding everything.
Have a great day! By the way, we’ve had our first snow; water temp is sitting in the high 30's right now. Just about time for me to pull the pumps and shut down for the mildly brisk weather that we’ll be experiencing for the next few months!
Very thoughtful response DRH2.
First snow, eh? After the unseasonably warm summer we have had I wish it was me over here with a first snow. I'm ready. I want a fire in the fireplace with snow flakes hitting the windows.
Thanks DRH2 9 (and all) for your great advice and explanations. I typically keep the gravel filter cleaner, but the sudden downfall of leaves caught me offguard.
You're right, the pond seems to be returning to normal but I've kept the air stone running 24/7, and will for the forseeable future. The water temps have cooled even since I was in the pond earlier this week, and the fish seem to be doing okay - no gasping at the surface for several days.
I didn't get to do a water exchange today - most of my day was spent getting leaves out of the yard due to an encroaching storm front passing our way tomorrow (four HUGE silver leave maples can drop massive amounts of leaves, not to mention the dozen or so other trees that produce their fair share, too.)
Been reading this thread and wanted to state that activated charcoal will take care of those tannins. I bought mine at a pond store but I understand that you can use the horitcultural stuff found in the potting soil section of HD or Lowes. Correct me, DRH2 or Lauren, if I'm wrong about that.
When I first set up my pond I had plenty of tannins and the water, thought clear, was a nice tea color. I put a filter bag full of activated charcoal into the skimmer box and a few days later it was clear.
I believe the term horticultural grade refers to the size of the activated charcoal. In other words, it's a little bit larger than that which would be found in those little mesh bags that they charge you an arm and a leg for. Stick it in a cut off panty hose leg and tie off the ends and go for it. Anything goes. I've got little green army men in one of my biofilters and some left over pink plastic hair curlers that I bought a whole box of from a salon that went out of business a long time ago for $1.
It'll work but tannins aren't necessarily bad so I leave my pond water as is. It's clear, it's just slightly tea colored in two ponds. I once read somewhere that the presence of tannins somewhat inhibited algal growth. Some people like tannins because of this but I've not noticed any significant difference in algal growth in ponds with and without tannins. I think algae happens. If you want your pond to have crystal clear water, then add activated charcoal to your filter when it gets tinted. You'll have to replace it every now and then.
That activated charcoal sold for ponds is pricey! I got mine at a pond store and it came with a filter bag. With a pond my size, it took two boxes. I read somewhere, can't remember where, that if you want to use the same charcoal for awhile, you can soak it in bleach, rinse, and dry in the sun. Do you know anything about this?
I never tried that.
You can use activated carbon, or not - it’s your choice. It will adsorb tannic acid (and other organics as well) but, as Equillibrium has found, I find that they breakdown fast enough just with the ol’ biofilter. The big thing is to keep the leaf litter down to a minimum (specially oak leaves and pine needles). Without the leaves no more tannins. As to regenerating activated carbon - I highly doubt that bleach (chlorine) will have any significant effect on regeneration of the carbon. First, the chlorine would have to get into the pores to do that. However, activated carbon is very good at destroying chlorine (also called “free chlorine”, hypochlorous acid, hypochlorite ion) as well as chloramines. As a result before the chlorine could do much to the tannic acid it would react with the activated carbon. A second problem is that you may also end up creating a chlorinated hydrocarbon of one sort or another on the activated carbon. While this is unlikely to be released once the carbon is placed back into the pond environment it’s nothing I’d want in my pond. In fact one of the major problems with chlorine as a disinfectant is that it has so many side reactions with humic acids, tannic acids and other dissolved organics. Its one of the primary reasons many municipalities are switching over to chloramines for creating residuals in the water lines.
If you want to use activated carbon there are alternative sources that you might want to investigate. I had a friend give me over 125 pounds of the stuff that was being used in a water treatment plant (to remove those organics prior to disinfection). I played with it for a couple of years and decided it wasn’t worth the fuss, mess and cost (if I’d had to buy it myself)...that a little bit of extra biofilter wouldn’t easily handle. That alternative source? Talk to your local water filtration plant folks. They may be able to get some for you (although I suspect they’d rather not be doing that on a regular basis) or they should at least be able to identify who they buy activated carbon from. This would mean that you’d be buying commercial quantities - typically 50 to 200 pounds minimum of “stuff” which may translate into a lifetime supply depending on your pond size! :-)).
That is excellent information. I wish I could remember where I read that bit about the bleach, but no matter. It didn't sound like something I wanted to mess with anyway.
I do happen to have a bit of a connection with our local waste water treatment facility as my DH used to work for them many years ago. Same people are still there, except him. So I'll check it out.
I have found that that adding this to my skimmer increased my water clarity in a way that is hard to describe, but easily recognized. It seems to make the water 'sparkling' clear. That's not a very scientific term, but it's how I would describe it.
Are there other, less obvious, things that would cause tannins in the water? I got tannins right away when I started the pond, and leaves were definitely not the cause as the only tree near the pond is a laurel tree which sheds an occasional leaf, but not during the spring.
Pixydish, if you've got a bit of mulch around the pond (you decided to mulch all your plants because you're like me and don't want to weed, and weed, and... :-)) then if it washes in, water leaches through it into the pond or just plain splashes into the pond - this will all cause 'rootbeer water'. It's really surprising how far rain-splash will carry. Take a look at the side of a house that has just bare earth near it - you'll see mud as high as 2-3 feet! Also, if you've got flow through a 'bog area' which has peat moss in it you can get a bit of the 'browns'. And by the way, "sparkling clear" is as good a term as anything else!!!
Well, it's going to remain a mystery, I guess. But I haven't had any trouble at all with it since I put in the charcoal. Likely that charcoal is useless now, but the tannins are not back, so I'm good with that. Thanks a million for the info.
It sounds like, from Lauren's post above, I can definitely use the charcoal I found in the gardening section. I have an extra filter bag, so I think I'm set.