Buy new liner?

[Isaac Lo]

Yep, absolutely do not use a PVC liner. I know the cheaper price is tempting, but the liner is the very base of your build and if there's a tear or a hole it's really difficult to locate and repair. When I first started out I bought a PVC liner. What a mistake. PVC liners become brittle in a matter of a few months. Mine sprung a leak in the dead of winter. I couldn't replace it until the Spring, so every week I had to add 300 gallons until Spring came. I changed it out with EPDM.

As stated, most prefer EPDM. I'm in the middle of adding a bog and I opted for a HDRPE liner this time. I thought I would give that a try. It's quite stiff compared to EPDM. I hope it lasts as long.

Thank you! You saved me a lot of trouble. That sounds horrible.

I hope your big works well. I got a reply telling me that I should make one, but I don’t think I’m ready too.

 

[Lisak1]

I think water quality is an issue

When you think of water quality, you want to start with bioload. Too many/too big of fish are the most likely cause of poor water quality. Keep your pond UNDER stocked and your water quality will be fine. You said you built a "koi pond" - I think your pond is more likely a goldfish pond. My pond is around 4000 gallons and, after having (and losing) about a dozen big koi, we have chosen to keep our pond goldfish only. The are simply easier to keep in a garden pond as the biomass is much less and therefore filtration needs are greatly reduced. I would feel perfectly OK if our pump went out for some reason with just goldfish in the pond. With koi, that quickly becomes a problem.

I completely understand wanting to re-use the liner you already have. If you feel good about reducing the size of your pond, that's your choice. Most people want to go bigger! How big would you estimate your current pond is? "Digging smaller" can be an issue, as you need to backfill and make sure you compact, compact, compact the soil you return to the hole. You don't want the edges around the pond to start to sink or settle which is what will happen if you don't make sure to they are firmly packed. I would even suggest you compact the soil and then wet it down and compact it some more.

 

[Isaac Lo]

Your liner is the most important part of your pond. Don't waste your money on a cheap liner, 45Epdm is what most people use. 1 foot overlap gives you room to work. Once you fill the pond, the died will compact and it will settle. Better to have extra liner around edgevthan a low spot where water can leak out.

Thank you for the advice! Is a foot overlap required or just advised? The liner I have almost fits.

 

[Isaac Lo]

When you think of water quality, you want to start with bioload. Too many/too big of fish are the most likely cause of poor water quality. Keep your pond UNDER stocked and your water quality will be fine. You said you built a "koi pond" - I think your pond is more likely a goldfish pond. My pond is around 4000 gallons and, after having (and losing) about a dozen big koi, we have chosen to keep our pond goldfish only. The are simply easier to keep in a garden pond as the biomass is much less and therefore filtration needs are greatly reduced. I would feel perfectly OK if our pump went out for some reason with just goldfish in the pond. With koi, that quickly becomes a problem.

I completely understand wanting to re-use the liner you already have. If you feel good about reducing the size of your pond, that's your choice. Most people want to go bigger! How big would you estimate your current pond is? "Digging smaller" can be an issue, as you need to backfill and make sure you compact, compact, compact the soil you return to the hole. You don't want the edges around the pond to start to sink or settle which is what will happen if you don't make sure to they are firmly packed. I would even suggest you compact the soil and then wet it down and compact it some more.

Okay I understand. I don’t think that was the issue. There was a rather green color to my pond (I assume from the algae). And it was murky with dirt that spilled into it. I understand now that koi’s are for bigger ponds but my mom really loves them. I hope I can get at least one or two little koi’s and the rest goldfish. As a side not I heard you have to prep the water using beneficial bacteria. Is this true?

I would really like to go bigger too! I’m just not sure I can justify it. I don’t want to waste liner because my calculations were incorrect, but I’ll do it if I have to! I would guess a little less than 1,000 gallons. Thank you for the advice about the “undigging ”! The soil not being compacted actually happened to me because I was making a wall flatter and the wall fell in! ( that’s how the dirt got in the pond )

 

[Lisak1]

little koi’s

There's literally no such thing as "little koi". They start out the size of an eyelash and grow VERY FAST. Have your mom look at shubunkin goldfish. They have all the lovely colors of koi and are the perfect size for your pond.

If by "overlap" you mean the amount that you have around the edge, a foot is fine. If you do want to go bigger AND use your old liner, check out the post by @GBBUDD on seaming two pieces of liner together. He did it in an existing pond - far easier to do if you can lay the two pieces of liner flat to create the perfect seam.

 

[addy1]

He wrote up a real nice piece of seaming liners, It is stickied in the construction thread.

Seaming EPDM liner

Seaming is not difficult but it does require some foresight and thought. Hopefully this list will help you to create a seam that will last for many, many years, issue free. If you can seam your liners in a driveway or somewhere flat that is by far your best option. The method below is how I...

www.gardenpondforum.com

 

[poconojoe]

I advise staying away from seaming any liners. If not done correctly with all the proper materials, the results can be very frustrating. You don't want to fill your pond up, add everything, including fish, then find out there's a leak in the seam. Trust me, the liner is the very base of your build and you want it to be perfect.

I'm not sure if it was member GBBUDD or maybe someone else that struggled with this and after a few tries, finally got a good seal. I imagine it was quite frustrating.

If you want to increase the size of your pond, buy a bigger liner. You can use the old liner to build a bog filter next to the new pond. You can read about bogs in these forums.

 

[mrsclem]

Agree with lisak regarding little koi. I have had year old koi 20"! Shubunkin are the way to go. I love them but decided to go total koi with my 2 ponds. Over 9000 gallons.

 

[Isaac Lo]

Agree with lisak regarding little koi. I have had year old koi 20"! Shubunkin are the way to go. I love them but decided to go total koi with my 2 ponds. Over 9000 gallons.

Okay! Thank you, I didn’t know that guys. Hmm it’s unfortunate though. If I had one or two big koi would they kill my other fish? Sorry to ask you guys so many questions, but how many gallons of water would you advise for two koi?

 

[Isaac Lo]

There's literally no such thing as "little koi". They start out the size of an eyelash and grow VERY FAST. Have your mom look at shubunkin goldfish. They have all the lovely colors of koi and are the perfect size for your pond.

If by "overlap" you mean the amount that you have around the edge, a foot is fine. If you do want to go bigger AND use your old liner, check out the post by @GBBUDD on seaming two pieces of liner together. He did it in an existing pond - far easier to do if you can lay the two pieces of liner flat to create the perfect seam.

Thank you guys for the advice! I think I’m going to buy a new bigger liner (I’ll make sure to stay away from PVC, thanks poconojoe). I want to use the liner, but I don’t think I have space for a bog. I appreciate the idea though. Would it be a waste to use the old liner as a cushion?

 

[poconojoe]

If you have a low fish load, a bog can be 15% of the surface area of your pond. But if your fish load is large or you keep koi, then it should be 25%-30%.
You can use your old liner for a bog. I highly recommend a bog and maybe your bog doesn't need to be that big.
I wish I would have known about bogs 12 years ago instead of wasting lots of money and performing all the maintenance on commercial filters that turned out to be inadequate.
So, it's up to you.

You can use your old liner as a "cushion", as you say, but if you leave it under your new liner water can get trapped between them. It's advisable to poke many holes in the old one before laying the new one over it.

 

[mrsclem]

Okay! Thank you, I didn’t know that guys. Hmm it’s unfortunate though. If I had one or two big koi would they kill my other fish? Sorry to ask you guys so many questions, but how many gallons of water would you advise for two koi?

Koi won't kill other fish. The general rule is 1000 gallons for 1 koi, 500 for additional. The big thing is having adequate filtration. Currently i am way overstocked. Had planned on rehoming a lot of mine but now with the virus situation, a fish sale is out of the question. Cleaning filters and pumps every other day!

 

[addy1]

Go bog! lol I never clean filters, never really fuss with the pond once I turn it back on. When I built it the bog was my filtering system. I refused to build a pond I had to fuss with, i.e. clean filters etc. I am a lazy ponder................

 

[Lisak1]

If I had one or two big koi would they kill my other fish?

They won't kill your fish... at least not on purpose. But too many fish in a pond will kill ALL the fish because of poor water quality.

 

[Isaac Lo]

Thank you guys for all the replies!
I’m trying to figure out whether or not to make a bog. They sound really amazing but I’m not sure I have the space to put it somewhere. I’ll keep researching and I will update you guys on how it goes!