Changing pond liner

[Noompsy]

Hello everyone, I thought I would try to get some feedback. I have never gotten any advice and have done everything myself to this point but thought I would get some input from other Koi owners in this scenario.

I am swapping out my pond liner currently. When I started this I bought a very cheap pond liner because I didn't know how all of this would end up. I have moved all of my koi to a 300 gallon tank until I get it done. I ran an inlet into the tank and a return to keep my bog cycling and to keep the water clean while the fish are in the tank. I will say right off the bat and will probably get a lot of criticism for it but, I have a LOT of fish.

My pond is about 4,000 gallons. I run two filters, a skimmer and waterfall/spillway with bio balls. I run a bio pressure filter and a 300 gallon bog I made myself.

I started my pond 6 years and have never lost a single fish, not one. Even the goldfish I bought at PetSmart for 12 cents to start the pond grew up, multiplied and grew almost to the size of small koi fish. I have since given away all of them and only have Koi fish now. I have given away thousands of fish every year after spawning but a lot of them hide very well, so it's hard to keep up. Now that I have moved them all to the tank I will be giving away about 80% of them before filling the pond back up.

My water is ALWAYS perfect when I test it (once a week). I don't know why, I don't know how, but it is, always has been. Even when I show pictures to the fish stores and people I have bought plants from in the past, the question is always "why is your water so clear"? I never have an answer for them, it just always is and it always looks like drinking water.

My fish range in age from 20 years old ( customer gave me four fish over 20 inches) to 6 months old. I have at least 6 fish that are over 20 inches, probably 15 that are about 14 inches, 15 that are 8 inches, maybe 15 that are 5 inches and the ones that are small from June of this year, about 30 of them. All of my fish are from the same 4 fish my customer gave me 5 years ago. I am going to introduce new fish to the pond after I give away the majority this week.

So, now that I have given a little history. I was wondering if someone could tell me how long I need to wait to put the fish back when I fill the pond? I read a few threads on here before starting this one and none of them have the specifics that mine pond has.

I have two pumps running 24/7. One pump goes through a skimmer with a filter and then into my bio filter, and that one pumps at 5,200 gph. My bog has a pool pump with a 2hp motor with a 4" pipe and pumps about 6,000 gallons per hour. My plan was to continue to run one pump in the holding tank and cycle the other one with the new water. I just don't know how long I should do that before returning the fish back to the pond.

I have attached picture of my bog and the holding tank with the fish in it.

 

[JRS]

Welcome to the forum Noompsy. Are you concerned about establishing the biofilter for the new pond/water or the safety of the water itself? Sounds like you have your filters intact at the moment, or has one been shut down during remodel? With that amount of fish I would reintroduce them to the main pond ASAP once the water is treated and temp stabilized, assuming you route your currently running filter back the the main pond.

 

[Noompsy]

Thank you JRS.

I was just worried about the water since it will be 3,500 gallons of new water. I will be putting back 500 gallons of the original water and the bog has never stopped running so I'm sure that's good. It's just a lot of new water that I am worried about putting my fish in. They have done so well for so many years with minimal water changes and this is a lot of water.

I have also decided to replace my bio filter with a new one since I am having to do some pipe work and the filter was off for about 48 hours anyway. I will say, my bog is just amazing. I put the fish in the holding tank with an air stone and a little cheap filter. It took about 12 hours for the tank to look murky and ammonia levels to spike. I did a temp inlet pipe into the tank to the bog, it cleared up the water and blasted the ammonia within 4 hours.

So I guess the real questions is....

Is it safer to leave the fish in the holding tank for a few days to let the new water cycle? Or should I put them back right away into the new water? I posted pictures of what I was talking about in terms of the performance of my bog. The pic with the clear water was taken less than four hours after the murky water pic.

Side note: I am adding Aquascape beneficial bacteria water treatment contractor grade to the new water tomorrow.

​

 

[j.w]

@Noompsy
What a beautiful herd of koi! I would have a heck of a hard time deciding on which one's to keep

 

[Lisak1]

We went through a full pond clean out last summer - essentially same size pond and a similar amount of water in reserve. We opted for getting the fish back in the pond as quickly as possible, but we have only one big koi. The rest are goldfish. We did lose one fish in the process, but that was due to his poor decision to leap out of the holding tank.

 

[Noompsy]

Hi LisaK,

When you say "opted for getting the fish back in the pond as quickly as possible", how quickly was that? Did you treat the new water with anything? Did you cycle the new water through your bog for any time before you put them back in the pond?

Thank you for responding to my question.

 

[Lisak1]

We had our fish out of the pond for maybe 30 hours. Cleaned the pond and refilled it on the first day. Returned the fish to the pond the next. Waterfall ran for 24 hours so we knew any chlorine was gone - we don’t have chloramines. The water the fish were in went back to the pond - mostly. I didn’t pump to the bottom of the holding pool as it had settled and was a bit dirty. We did set up a temporary filter on the pool and covered it with netting overnight to keep the fish safe from predators and their own instinct to jump.

I’m not saying this was the best or recommended way but we weighed out the stress of being in the holding tank vs getting them back into the new water and opted for the latter. Also we made attempt to scrub the pond clean. There was lots of algae and even dirt left - especially around the base of the plants - so we felt the bacteria would quickly repopulate and get the pond back to its previous condition quickly. We never experienced an algae bloom or new pond syndrome so it seemed to work.

 

[GBBUDD]

Empty about half the water , so 150 gallons , then add water from the new pond to the holding tank slowly like they were coming home from the pet store. After an hour or so if temps are common and start to move them to the pond with a koi sock