Darn, I think I have a leak - not all bad news

[GaryMoz]

I've been scratching my head recently trying to work out why the pond is using so much water.

I managed to get to my water meter readings and can see how much it is using, it seems to be using 700litres day, that's an extra 20m3 a month (5000+ gallons)

I do have a drum filter so that could be using a lot, but doing tests, it only using 100litres max a day. On summer days evaporation could account for a lot but not this time a year, again 100 litres a day. So that leaves a shortfall of 500 litres.

Now I've got the water usage I see the water usage went up after I changed the overflow height, original it was too high and the drum filter overflowed. I think the seal below the new overflow is not good and water is being lost.

It should be a simple test, turn the auto top up off and if I'm right I may loose a 10-20mm of water quickly and then it should slow.

I hope it's that and then it should be a relatively simple fix, if not....

 

[Lisak1]

Don't underestimate cold, dry weather evaporation - I just had to top off the pond this weekend. First time since mid-September.

 

[GaryMoz]

Don't underestimate cold, dry weather evaporation - I just had to top off the pond this weekend. First time since mid-September.

I've used an evaporation calculator and currently the amount is low, just 50 litres a day

 

[teeemkay]

I've been scratching my head recently trying to work out why the pond is using so much water.

I managed to get to my water meter readings and can see how much it is using, it seems to be using 700litres day, that's an extra 20m3 a month (5000+ gallons)

I do have a drum filter so that could be using a lot, but doing tests, it only using 100litres max a day. On summer days evaporation could account for a lot but not this time a year, again 100 litres a day. So that leaves a shortfall of 500 litres.

Now I've got the water usage I see the water usage went up after I changed the overflow height, original it was too high and the drum filter overflowed. I think the seal below the new overflow is not good and water is being lost.

It should be a simple test, turn the auto top up off and if I'm right I may loose a 10-20mm of water quickly and then it should slow.

I hope it's that and then it should be a relatively simple fix, if not....

I hope it’s an easy fix. I’m dealing with a tough leak scenario too, which is the last thing I wanted with a one-day cold snap cold enough for icing setting in.

 

[Lisak1]

I've used an evaporation calculator

What is that exactly?

 

[NotMike]

What is that exactly?

It’s a calculator, you can look it up online. You type in pond size, humidity, temperature and wind speed into an online form and you get an answer of the number of litres per day that you loose to evaporation.. approximately.

 

[j.w]

It’s a calculator, you can look it up online. You type in pond size, humidity, temperature and wind speed into an online form and you get an answer of the number of litres per day that you loose to evaporation.. approximately.

Well I found one..............did not even know they existed!
https://www.omnicalculator.com/physics/evaporation-rate

 

[GaryMoz]

Well I found one..............did not even know they existed!
https://www.omnicalculator.com/physics/evaporation-rate

Yep, that's the one

 

[GaryMoz]

I was hoping it will be a simple, but it's not going to be. I had thought there may of been a leak around the overflow flange, but it's dropped 40 mm so far, so gone below it and the rate of loss is not slowing down. Because the rate hasn't slowed down it makes think the leak must be deep.

 

[GBBUDD]

Well my friend it is that time of year, shut down the pond is not a problem. , add an air source and see if your water level starts to drop if it is deep and it keeps dropping , then plan b to over winter the fish in a temp pond or maybe a fellow hobbyist in the area maybe in your future

 

[GaryMoz]

Well my friend it is that time of year, shut down the pond , add an air source and see if your water level starts to drop if it is deep and it keeps dropping , then plan b to over winter the fish in a temp pond or maybe a fellow hobbyist in the area

That does make sense, I can isolate the bog filter and that will indicate if the leak is in pond or bog. I hope it is in the pond and not the bog, (if it is in the bog I have no idea how I could fix, I'm moving 15 tons of stone).

I'll keep monitoring the water and hopefully it will slow down before it empties all out.

 

[GBBUDD]

I REBUILT MY BOG TRUST ME I FEEL YOUR PAIN. IF indeed it is the bog. did you put any underlayment in to prevent the stones or aquablocks from being against the liner? i only rebuilt mine to addr 24 inches of waterfall.

 

[GaryMoz]

I hope it's good news. I've been measuring the water lost recently and turned the pond off, all the pumps, ball valves etc.

I've put the numbers into excel and a graph, bearing in mind my measurements are quite crude you can see on the left and reasonable contact lost of water, on the right it shows the values after the pumps and valves are closed. After a short while it evens itself out, with water leaking out and around the waterfall into the main pond.

Taking into account the water leaking from the bog into the pond, you can the the water loss has slowed right down.

I think it shows the leak is not in the main pond and I don't think it is in the bog as the water loss seeping into the main pond is also slowing down as it gets to the bottom of the waterfall stone.

So I think it shows the leak is either at the top of the bog or more likely somewhere in the pump room, I could see some water in the pump room but not enough for 400-500 litres a day, but I will have to tune back and take a better look.

I can also take a good look around the top edge of bog liner and around the waterfall stone, perhaps I damaged the liner when I fitted it.

Having a hole in the top of the bog liner or a leak in the pump room should be a lot easier to solve than one down deep

 

[GBBUDD]

With welded seems its not uncommon with changing on seasons for seems to stretch and open up. The bad news is the most they show this has happened is just a dark line at the seam. This is about twice as wide as what looks like a normal seem. Did you happen to caulk the seams when they we done? The other way to see if there is an issue with a seam is to push on if or use your finger like a squeegee and look for water or air bubble.

Unfortunately in a multi angle meeting area such as bog wire to bog retaining wall both inside the bog and out. And the cut out where the bog wall raises is a lot of angles to make with sheet goods. In epdm the use of uncured rubber makes this easier . Did your installer make his corners or did he modify factory made corners?

Did you check anywhere the liner folds over its self see if it wicking especially along the edge of the bog.?

Now that you have a feel for where it might be it maybe worth draining to the bottom of the weir.

One last spot id look at is return jets over tightening is a common problem