How do I waterproof a fibreglass pond?

[likepizza]

  

 I moved to a new house and the fishpond had cracks in it. I patched the cracks with a fibreglass repair kit. I’m pretty sure I got all the holes and gaps. I put some water in to test it and it seemed to hold well. But overnight the water level dropped about 50mm. Looking at the pond it seems like water has seeped into the fibreglass which is probably 30 years old. Can I use Crommelin pond sealer to fix this?

[Jude2]

Drained, dried & painted!

Next step will bet  th he fish & plants. 

 

[MitchellMc]

Lovely work, @Jude2! Many thanks for updating us on your project. The results you've achieved look wonderful.

Please give us another update when you start planting and introducing fish.

Mitchell

[Jude2]

Baby fish now in, & happy. Just waiting for the big ones to return from holiday. 

 

[EricL]

Hi @Jude2

Thank you very much for posting your fish pond project. It looks fantastic and I'm sure your little fishies will thrive in their new home. What kind of water pump did you use for the pond? Can you also please tell us the plants you've decided to put in? 

Again, thank you for sharing such a wonderful project.

Eric

[Jude2]

 These are the pond plants I used. I also have Liriope, day lily & native violets up to the edge to give insects hidey holes. Big fish are now back  & seem very happy😍

 

[Jude2]

Pump was from bunnings. Not sure if the size - that’s the other half’s job. Pond holds about 300litre so he would have gone for a pump with that as mid range capacity. It needed to be stronger to push the water up1 metre to run down the wall

[Aquaman]

Apparently not it doesn't stick to fibreglass 

[MitchellMc]

Hi @Aquaman,

To clarify, fibreglass is not a surface that the supplier has in their recommended list of surfaces for pond sealer as it is flexible and changes dimension when it heats up and cools. The sealer might very well stick to the fibreglass; it's just the supplier can't verify that it won't crack or delaminate at a later stage.

Mitchell

[Aquaman]

And there lyes the issue as I'm building a indoor plywood aquarium 

Perhaps you advise on this is, is there a No VOC non toxic black sealant that bunnings carry

[MitchellMc]

Not as far as I'm aware @Aquaman. Achieving no VOC for a sealing product would not be easy due to the qualities they need to possess. Even LOW VOC wall paints are a relatively specialised product. Many products stop off-gassing completely when they've cured, but if this is inside, you'd likely need to ventilate the area until that occurs. Could your aquarium be built outside and sealed before it's bought inside?

Mitchell