Outdoor Aquarium Problem

[gsparsan]

I have a 6ft outdoor aquarium installed some 18 months ago. The tank was tested full of water before use. Since then I've had several problems with the tank. The first problem was the tank opening up along one vertical edge. It was the silicon that had split. It was repaired and reinforced. A few months later the same thing happenned on the opposite side. This time it was repaired and reinforcement was applied to all other sides. Six month later (last week) it is the bottom edge of the front panel that opened up. Fortunately in happened right in front of me and I managed to save the fish. In 15 mins the whole tank was empty.


What am I doing wrong? Is it the sun that is degrading the silicon over time? All 3 times the incident occured during heavy rainfall. Can this tank be repaired again? Any modifications that you would recommend?

http://picpaste.com/DSCF2762.jpg
http://picpaste.com/DSCF2763.jpg

 

[Coler]

It's hard to say but here's a couple of pot shots :-

1. I don't like the way the tank is overhanging the styrofoam underlay at the front and perhaps this is causing strain to the front panel.

2. I don't know the provenance of the tank, how old it is etc. Admittedly, if tested properly, this should not be a concern - for me with a tank that was new to me I would want it filled for at least a couple of weeks with no leaks before I would trust it.

3. Noting that it happens during heavy rainfall it would seem that the tank is becoming overfilled when this happens leading to the seams splitting.

As regards what you could do now, I think at minimum to trust this tank you would want it emptied, dried out and fully resealed by a very competent person, then filled and observed for a couple of weeks to ensure it has been done properly. I would also set it up so that it is completely seated on the airboard underlay as opposed to having any part of the tank overhang.

As the problems happen when it rains, look into an appropriate lid that prevents water ingress but still allows for aeration - some kind of overhanging canopy type arrangement - doesn't have to hang high over the tank, just something that has a gap between it and the top of the tank to allow for gas exchange.

 

[Sploke]

If it is on a wood stand (which it looks like) the times of heavy rain might be affecting the stand as well. Wood expands and contracts with moisture (i.e. rain or humidity), and with the tank and stand being outside and subject to changes in temperature, humidity in the air, and moisture due to rainfall, if the stand is warping or flexing as it expands and contracts, it will put pressure on the seams that they were not meant to withstand, leading to eventual failure.

 

[Coler]

^ Great point.

 

[Bushkill]

I don't think a tank can be dismantled/repaired outdoors without ambient humidity affecting the bond between silicone and glass. So my question here is upon the first failure, was the repair done outdoors?

Some other thoughts / questions:

What adhesive is being used?

What thickness is the silicone bead between the panels and are spacers used between them?

Could you show a full picture of the eurobracing around the top perimeter? I have a feeling there aren't bracing strips along the front and back panels?

 

[OrionGirl]

Most aquariums are not built for use outdoors. Too many changes, exposure to too many elements. Not good.

 

[Rbishop]

And as for the stand, the above points were great. Is it just the angle of the shot, or is the overhang at one end look much larger than at the opposite end?

 

[gsparsan]

Thanks all for the response. The main frame is of reinforced concrete with Balao timber on top. The concrete frame is only 5 foot wide whereas the tank is 6ft wide, hence the overhang by about 6" on each side (well, 5" on one side and 7" on the other). The timber planks are 6ft long and overhand on each side of the concrete. The front and rear panels edges are double thickness (2x8mm) and there is one central cross bracing linking the two panels together.

I don't think its over pressure as it was tested at 100% full and indeed operated at almost 100% for over a year. The tank is covered by suncreen fabric and did not fill up completely. It was up to about 75% full when it happenned.The guy that built the tank thinks it may the the sun overheating the silicon. I can admit it happen on the top but on the sides and bottom (i.e. under water) the silicon will be at about the same temperature as the water, even in the sun. He has built several other tanks like this one and never had any problem but then mine is the only one that is kept outdoors.

When dry the planks are perfectly flat on the concrete but I get your point about humidity and warping of the planks. This may be it. The problem happened after 3 days of non-stop heavy rainfall.

Can the same tank be modified into a 5ft tank? That way the tank can be supported directly on the concrete frame and I can get rid of the planks. This should resolve the problem of warping. That would be fine for the comets but probably a bit tight for the ID sharks. I intended to transfer them to a large pond (6m x 12m) when they grow too big for the tank anyway.

Is the foam sheet of any use at all or is it better to put the tank directly on the concrete? The surface of the concrete is flat but not perfect.

Will it help if I use the same tank but with a welded steel frame all around it from say 1.5" angle bars ? The glass panes can be siliconed to the frame.

 

[rufioman]

It sounds a bit...dodgy. The whole outside thing and weather variables are making it kind of iffy for me.

Having said that, you could put a rubber gasket or something underneath the tank so it isn't directly resting on the concrete. Or just a piece of water sealed wood? I dunno, I'm new to outdoor tanks :/