Will it need to be sealed

[blocka]

Hi every one after some advice I've got a 5000 gallon concrete water tank at home that we no longer use and I'm thinking of attempting to cut in half and useing it as a pond question is will the concrete be safe for the fish or does it need to be sealed with pond sealer thanks

[rainbowrunner]

I believe it should be sealed as the bare concrete secretes lime and raises the ph . . . alot

[Aquatic Paradise]

As RainbowRunner mentioned it is likely to leach lime which normally raises the PH to 7.5 - 8, I don't know of any concrete which makes it higher and older tanks are generally fine, the rainwater from our farm tanks is PH 6 and soft because it has built up a layer of biolife.

Depends what you want to put in them as well, African lake fish, most brackish fish and Goldfish are fine with 7.5 to 8 so you should not need to seal the tanks, but soft and acidic water fish would not fair so well.

[blocka]

Thanks for the info

[nickm986]

I'm no expert on cutting concrete tanks in half, however I have seen plenty made.

Have you put thought into the actual cutting of the concrete? There is a fair amount of rio in the walls of a tank...

Plus if its pretty old as soon as you hit it with any power tool the whole thing could crumble?

[blocka]

Probably a big concrete saw or if I put it in the to hard basket there's a 10000 gal poly tank I can cut up but I've got to try get it up to the house from the paddock and fit it somewhere

[Aquatic Paradise]

go the poly tank

[speet]

Sounds like a mission, would love to see pictures of this as you make progress.

[fishyj]

You might have a problem with Oxygen levels as well. I have read about the closed bioshere in the USA. Where the scientists lived in a sealed system and the 20.9 % oxygen levels dropped to around 14% in less than 12 months. It was discovered that the bare concrete in the stucture was absorbing oxygen faster than the flora could recycle it. (It wasn't factored in to the original modling.) This resulted in decreased mental health and a whole bunch of physiological problems for the test subects inside.

Now your system is not closed as such but you may need to add extra oxygen and there for extra cost.

Cheers Jason

[zorbadundee]

Concrete matures @30 years so if its around that age it will be harder to cut, but if you could I woudl cut it seal it and try to cut some windows in it for side viewing woudl be a awesome setup that big, Just hope you are not planning on heating it.....$$$$$$$$. No tsure how big the concrete saw are to hire but go with a petrol one the samller electircs are a waste of time.

[blocka]

Over the concrete tank idea

[clayton31]

Lol piece of piss to cut as long as u don't want the top half also depends how thick the walls are a hand saw can only cut 145mm new blade 150mm ..if any thicker ud have to go ring saw that gets expansive ..but there is always trading fish lol

[shakey2277]

if you wanna heat it you should go solar since it will be outside

[savage_roo]

If you are still thinking of doing it, Its not that hard

Just get a rope and tie it to how deep u want it mark it with the rope and a spray can of paint

Get hire a diamond tipped saw cut threw half way in to the sides of the tank and get a hammer and brake off the top half then when you get it down closer to the cut .Cut it off the rest of the way o ya its easier to brake it off as you cut

Should take you a few hours but it will be a great pond