Just changed water, thin green coat

[jake_warren]

Hi everyone, looking for advice from anyone with similar experience. I've just changed all the water in my 3000L pond. Scrubbed all the algae out and cleaned the pump and filter. Just 3 days after changing all the water, there's a thin green coat covered in bubbles all over the liner. I haven't tested the water yet, but I'm guessing the culprit could be overfeeding or overcrowding with not enough plants + the warm weather at the moment. Am I on the right track?

Thank you!

 

[poconojoe]

Tell us more about your pond and why you did what you did.
If your water wasn't clear due to floating algae, then you might have too much of a fish load, insufficient filtration and or too little plant life. This can be corrected in a few ways. Obviously more plants, more filtration or maybe a UV light in some cases.

What kind of fish do you have, how many and how large are they?
What type of filtration?
Do you have any plants? Plants are an essential component of your pond's filtration. The more plants, the better. Remember, algae, moss etc. are also plants.

I hate to tell you this and I don't mean to offend you, but It is never advised to completely change all your water, scrub your liner or completely clean out your filtration system, especially all at the same time.
You are now starting completely from scratch. You got rid of all your pond's beneficial algae and bacteria which are part of the natural cycle. All that good algae you scrubbed off you liner was part of the natural filtration.
Your filter also had beneficial bacteria living in it that is also part of this cycle.
It will take maybe a few weeks to get some of that regenerated.

In the mean time, patience is important. Give it time. And plants....its amazing what plants can do. You can add floating plants. They don't need soil or pots to grow in. Just throw them in. Water lettuce, water hyacinths etc.

Hope this helps. Good luck and looking forward to your response.

 

[jake_warren]

Hi poconojoe, thanks for your response.

I had a lot of filamentous algae stuck to the liner, probably about 8 inches long and covering the entire surface, plus a lot of algae continuously rising to the surface. The water itself had turned almost brown. Found one poor goldfish dead covered in algae.

I've got 9 goldfish and 1 koi, though I did have 14 goldfish. I only confirmed some were missing when I emptied it out!

I've got three oxygenating plants down the bottom (3FT down) of which one is a water lily.
There are two plants on the shelf 1FT down around the rim and one floating plant. My filter is the Filtoclear 12000 with a UV light built in.

I thought as much about completely changing the water, but I felt it was the best thing to do. One goldfish died and the others weren't eating properly. After using an algae treatment for about two weeks I suppose I turned to a complete change as a last resort. I used a full tub of starter bacteria after the change.

Sorry I can't tell you exactly what type of plants I have, I'd have to have a look for their labels and find out. Considering the sudden green coating so soon after a complete water change, you must be right about the culprit being either too many fish, too few plants, or insufficient filtration (Which would be a shame, it was an expensive system!)

A bit of an off topic question now, but with regard to the shallow water plants around the rim, do these need to be potted and given aquatic soil, or could they just sit and be held down with rocks etc?

Thanks again for the reply!

 

[poconojoe]

Sorry you had some fish die. That always sucks.
It sounds like your equipment is good so give it time, it will come back. Dont worry about the green stuff, it should dissipate when everything starts to cycle.
Watch your ammonia levels. If you dont have one, you should get an api test kit. The one with the liquid reagents. The test strip type are not as accurate.
As far as the plants on the shallow shelves, there are a few different ways people do this. It's best to not restrict your plants to a pot. Not only does it restrict the roots, but they also have more exposure to the nutrients in the water without a pot. Instead of soil, some people use pure clay kitty litter as a growing medium and rocks to hold the plants in place. You have to make sure you check the ingredients of the litter. Pure clay, no additives or perfumes. Its usually the plain cheap litter. The clay is also good for your water quality. You can also buy or make mesh bags to hold the litter. I use the mesh bags. I got them on Amazon. They come in different sizes and have a drawstring on top. Some people make them out of vinyl screening.

 

[Lisak1]

Good advice from @poconojoe . I will add one more bit - avoid chemicals of any kind, including algaecides. When you kill algae, you end up with a pond full of dead algae and there's nothing new algae likes better than dead algae. See the problem? Algae isn't a problem - it's a symptom. It's telling you that you have too many nutrients in your pond. It's also a solution, as it's consuming those nutrients that would otherwise create a deadly situation for your fish.

At roughly 800 gallons your pond is too small for even one koi, let alone a koi plus a dozen or more goldfish. Time to start thinking of a larger pond or a new home for that koi. Your pond is perfect for goldfish.

Also - the term "oxygenators" is somewhat misleading. Plants DO put off oxygen during the day... but they reverse the process at night. Lots of plants are great in a pond, but they aren't a substitute for good aeration. And plants are the most helpful in the pond when they are planted directly IN the pond - on the shelves or in the margins with their roots directly in the water. Lots of ways to accomplish that, depending on your pond set up.

 

[jake_warren]

Thanks Lisak and poconojoe for your replies. I didn't realise this about the koi Lisa. The owner of the pond specialist's told me I could get one koi and two dozen gold fish into a pond of this volume. Though the koi isn't much bigger than the most of the goldfish, or what's left of them. Another dead today! I'll have to get a few more plants this weekend and try out the kitty litter idea.

Wish I had seen your reply sooner though Lisa, I just used an algae treatment yesterday. I'll have to avoid from now on. I suppose going forward the main thing to keep in mind could be a lot more plants, less fish for the moment, and no algaecides. Have to keep an eye on the food too.

Thanks again for the advice

 

[Lisak1]

@jake_warren - we’re all here learning together!