Corner not touching

[HuskerBioProf]

I had a rimless 120 gallon leak on me after only being up a couple of days, so I have a little aquarium PTSD. I have since abandoned that tank and started working on a 40 G breeder rimmed build. My stand is perfectly level lengthwise and diagonal with a 5' long level. The aquarium is also perfectly level lengthwise and diagram. However, one corner is slightly not touching the stand. I assume this is because the black rim is not perfectly level or the plywood is very slightly warped. This is a home made stand.

http://i1038.photobucket.com/albums/a467/TylerCMoore/D533661F-1911-4976-A199-C3AC85F1B8A3_zps7snzge6t.jpg


I have read a lot of recommendations on this, but I would love to hear your thoughts for my specific situation. If you have evidence to back up what you think I should do, that is even better. Will it be okay as is? Should I shim under the corner with a cut credit card? Do I shim the stand to make it unlevel but eliminate the crack?

I am really nervous of another seem break, but my last tank had a history of leaking and an unlevel stand (by someone else), so I keep telling myself it was a unique situation.

[Gaxmode]

Maybe look into a leveling mat

[HuskerBioProf]

I have read from numerous anecdotal posts that leveling mats on rimmed tanks are not a good idea because they don't allow the weight to be distributed directly to the rim (as is the design of the aquarium). Do you have an argument/experience against that?

[Sk8r]

The plastic rim is not the tank, I suspect. The question is where is the actual corner of the tank resting.h

[HuskerBioProf]

The plastic rim is not the tank, I suspect. The question is where is the actual corner of the tank resting.h

I am not sure I understand the question.. Can you rephrase it?


EDIT: Are you asking if the tank is actually resting correctly on the plastic rim?

[GimpyFin]

A leveling mat won't really help you and as you suspected, it's not recommended. IMO, if you want to even it out so the corner touches, I'd try and work between the stand and plywood top and not between the tank and plywood. I would definitely try and get it so at least all 4 corners make good contact with the plywood. If you have a hairline gap or two in the middle areas, that's fine.

[Sk8r]

The actual corner is inside that plastic shell. Its resting place is the important one. Can you slide a playing card under that corner?

[HuskerBioProf]

You mean could I slide a playing card between the glass and the black plastic rim? I really don't think so.

I can't shim under the plywood at this point. It is all stained with the trim glued on and the screw holes covered with wood filler, stain, and polyurethane.

Would there be a benefit to leaving a credit card under that corner to make t so it is touching?

The LFS still recommended foam under the tank, even though it is rimmed. They understood how many people do not recommend it, but say it has "always worked for them." There are a lot of anecdotes regarding tank levelness. It is hard to find real facts.

[Deefish714]

I don't recommend level foam under a rimmed tank at all. I recommend shimming between your structre and the ply board. like stated by other members.

[HuskerBioProf]

I considered shimming under the plywood before installing it but decided with how minimal the defect was, I thought the shimming under the plywood had a greater chance to make it worse than better. The same with sanding the plywood.

At this point, as mentioned, that is not an option. Can anyone say why foam is a bad idea in this case? Most people seem to just be relaying information from others. There are a lot of anecdotal experiences either way. Is there any reason why adding a credit card under that rim would be a bad idea?

[Sk8r]

I mean a playing card between that corner and the table at the point at which the glass corner stands.

[HuskerBioProf]

I mean a playing card between that corner and the table at the point at which the glass corner stands.

The picture is showing where the aquarium will actually sit, if that is what you are asking. It looks like the aquarium corner is not at the spot it will finally be, because it is not at the corner of the aquarium stand. However, the stand is longer than the tank (I had multiple people say that this stand should support a 40 breeder just fine without having the corners directly over the vertical 2x4s).

Aside from that... Why is foam a problem if it is rigid enough to prevent the bottom glass from making contact with the bottom glass of the tank?

[GimpyFin]

Shimming/leveling between the stand and the plywood ensures you get the most even support surface directly below the tank. If it was any spot but a corner, I'd say don't even worry about fixing the small gap. Foam is going to compress and conform to what is already there, it's not really going to fix the gap that exists. For rimmed tanks, the bottom pane is raised underneath so only the rim touches the stand. Putting a sheet of foam underneath the whole tank can cause it to compress around the rim and then potentially put stress on the bottom glass.

[HuskerBioProf]

What about putting credit cards between the tank and the stand?

[GimpyFin]

If it were me, I wouldn't put a card(s) directly under the tank between the stand. Unless you're filling that gap uniformly, a card can create uneven contact there which could cause added stress in that corner. Again, the only true fix I see is fixing the stand. You can try leaving it or adding a card underneath if you want. 40g is not huge, so it may be ok, not sure.

[HuskerBioProf]

I get what you are saying.

But if I even out the one corner's rim with a credit card, that would make all corners touching with a level tank. I don't see how that would add a pressure point, it would just make it so that corner of the tank would not be flexing when weight is added. It seems like if shimming under the plywood is not an option, the credit card leveling would be better than foam. I realize this post was me mostly just looking for what I wanted to hear (kind of the "will a mandarin be okay in my newly established 30 gallon tank?" equivalent).

I know I am not going to do the perfect option, but wanted to know how bad it would be without the perfect option and what the next best alternatives could be based on all the forum's experience.

[HuskerBioProf]

Thanks so much for all the responses! Any other thoughts?