Fish Tank Not Level ?

[nicky1200]

I have set up my 6ft fish tank and befor i set it up and made sure my floor was level. I made sure the floor was level and then built a stand with cerment blocks ( all the same size ) and then put a 2inch pollystiry under the tank to stop any presssure points but now i have noticed that the tank is not level. I have asked my landlord to make sure the floor is level and they have said it is and the tank is not level because of the ammount of water in the tank. I have surport on the left side of the tank and the right side but not the middle.The left side of the tank seems to have a lower water level than the right. The right hand side of the tank is more fill and has a higher water mark than the left side. Has stated the tank is surported on the left and right but not in the middle. I was thinking maybe the tank is bowing in the middle ?

 

[techen]

It sounds like its bowing, you should never ever have a stand that does not support 100% of the tanks base. The glass will bend/slide until it cracks and dumps the entire tank full of water through your house.

 

[Ch4rlie]

I would recheck all the flooring and stand is level with a spirit level if you have one. 
 
Does sounds like it is bowing a bit and that will crack the glass if too much pressure is applied by water and gravel.
 
If its not level, then your best chance is to empty the water and gravel out before the glass cracks and further damage ensues.
 
Agree with techan that its always best to have a purpose made or a very strong stand/cabinet for fish tanks and must cover/support the entire base of the tank.
 
Don't rely 100% on other people saying floor or stand is level, checking yourself is best.

 

[nicky1200]

The fish tank was 100% level when it was empty i messured it with a spirt level. I have just tested it with water in the and the spirt level says its level but there is a 1inch water diffrence. So on the left side of the tank there is 8 inch from the top so from top to water level and on the right its 7 inch.
 
Is 1inch diffrentce a lot ?

 

[Sophie]

The fish tank was 100% level when it was empty i messured it with a spirt level. I have just tested it with water in the and the spirt level says its level but there is a 1inch water diffrence. So on the left side of the tank there is 8 inch from the top so from top to water level and on the right its 7 inch.
 
Is 1inch diffrentce a lot ?

 
Any uneven measurement is a lot.
Having an uneven fish tank is asking for trouble!

 

[nicky1200]

I have polstry under the tank to stop pressure points i think that the tank has "sat down "  in side the poly on the one side and has not "sat down " on the other side. But a inch out is a lot. I have messsured the tank and the tank is level the spirt level says so the only thing that can be making the water level un even is that the its sitting down into the poly ?
 
Here is a pic of the tank

 
 
You can most probley see the diffrence....
I do not know why the tank is not sitting down in the foam...

 

[Ch4rlie]

Way too uneven. Can see straightaway you will eventually have problems with your tank structure
 
Definitely not level. The water is always level so therefore your tank and stand is unlevel, right side of tank in photo is lower than left side. Does not seem to be bowing but unsure.
 
Did not realise you already have fish in there, looks like a silver shark on left side, not sure about the other on right side.

 

[fm1978]

I actually think the polystyrene is too thick.

You only require enough to avoid very small imperfections that might occur at the tank base. That thick load of styrene has too much give. If the tank is only becoming uneven after being filled it's not likely the concrete or wooden base that's compressing that much...that only leaves the polystyrene.

 

[Ch4rlie]

I actually think the polystyrene is too thick.

You only require enough to avoid very small imperfections that might occur at the tank base. That thick load of styrene has too much give. If the tank is only becoming uneven after being filled it's not likely the concrete or wooden base that's compressing that much...that only leaves the polystyrene.

 
Good to know for future references.
 
I was not sure if polystyrene base at 2 inches thick was unsuitable or not as I've never had to do this.
 
As I understand it, newer popular tanks now have what you call a 'floating base', this is where the lower pane of glass at bottom of tank is raised and glued to the inside of the four glass walls of the tank. Then the bottom of the tank is placed inside a plastic base frame hiding this raised glass making it nicer therefore you won't need the polystyrene.
 
So will it help the OP if he switches the polystyrene from 2 inches to an inch or less perhaps?

 

[nicky1200]

Way too uneven. Can see straightaway you will eventually have problems with your tank structure
 
Definitely not level. The water is always level so therefore your tank and stand is unlevel, right side of tank in photo is lower than left side. Does not seem to be bowing but unsure.
 
Did not realise you already have fish in there, looks like a silver shark on left side, not sure about the other on right side.

 
 
Yes i filled it up added the sand etc and the fish and the had a look at the tank to see what it looked like full right up and noticed it was off. I will take a photo of the spirt level on top of the tank. Im guessing there will be a lot of stress on the left side of the glass...
 
The tank is only 3/4 fill tho. So maybe if i fill it up more it will weight more so will push it self down more in the poly ?

 

[Ch4rlie]

No, adding more water will not help at all.
 
In fact I think will make it worse to be honest.
 
I think fm1978 comment is correct, your polystyrene is too thick.
Its too soft therefore your tank is sinking into the polystyrene, just so happens its starting on right hand side and water pressure on right side glass wall will give away by either cracking or more likely your seal will give way.
 
Think you may need to put down a thin piece of polystyrene, so you'll need to empty the tank and remove the 2 inch polystyrene and replace that with a thinner sheet of polystyrene. 
 
How thick the polystyrene should be for your tank size, am unsure about. Hopefully someone will give details for that.
 
Sorry, there is no quick fix for that, but better to do this now before things gets worse.

 

[nicky1200]

No, adding more water will not help at all.
 
In fact I think will make it worse to be honest.
 
I think fm1978 comment is correct, your polystyrene is too thick.
Its too soft therefore your tank is sinking into the polystyrene, just so happens its starting on right hand side and water pressure on right side glass wall will give away by either cracking or more likely your seal will give way.
 
Think you may need to put down a thin piece of polystyrene, so you'll need to empty the tank and remove the 2 inch polystyrene and replace that with a thinner sheet of polystyrene. 
 
How thick the polystyrene should be for your tank size, am unsure about. Hopefully someone will give details for that.
 
Sorry, there is no quick fix for that, but better to do this now before things gets worse.

So you think that the tank is sitting down into the poly on the left side but not on the right making the right side higher ?

 

[Ch4rlie]

Judging by your photo, your right hand side of the tank is sinking into the poly so thats making the left side higher than the right hand side.
 
Its your poly thats causing this IMO.
 
You need to swap this poly for a thinner sheet of polystyrene. 
Think you should get 0.5 to 1cm of polystyrene, make sure your poly covers the entire base of your tank like you have with your current set up.
 
2 inches of poly has too much 'give' which makes your tank sink into it when extra weight like water is added.
 
EDIT : hopefully someone can give a more accurate thickness for polystyrene for your 6 foot tank, have read some people say up to 4cm is better for 6 foot tanks but there does not seem to be a recommended thickness as far as I can research.

 

[nicky1200]

So i have just has another look today and have noticed that the water level is a bit better it was a inch out yesterday but now its only 2cm out. Is 2cm much ???
 
EDIT: i just noticed there are 2cm into inch so its not got any better....

 

[fm1978]

You really need that number to be 0cm and 0mm...
 
If you're absolutely certain that the concrete blocks and the wood that's sitting on top is level then you really only need around about 1cm (some might suggest 1/2 inch) thick piece of polystyrene to 'iron' out any imperfections. You don't need much - it's only to take the pressure off the tank in case there's sand or grit or other hard bits of mess under the base of the tank that could crack the glass when it's filled.
 
I'd thoroughly recommend bolstering you concrete supports in the centre and even using a second piece of wood to spread the load underneath - is that some sort of chipboard/mdf you have under there already?