acrylic 6ft tank bowing??

sofaknlo · May 22, 2019

bought used few yrs back. just noticed other day that the sides have a bow to it. is this normal for acrylic. 72x24x30. should i be worried?? lol

BadFish619 · May 22, 2019

Mine was slightly bowed. It's a lit of weight pushing out. I was never crazy concerned just something I noticed. Someone else will know a for sure answer

sofaknlo · May 22, 2019

tank seams dont look stressed at all just weird i never noticed before. had it 2 yrs already

lapin · May 22, 2019

The deflection is caused by water pressure and the fact that acrylic absorbs water. Most mass produced tanks are on the border line of being too thin. Cost of being competitive. I have seen this in just about every tank from 55g on up. If they did not have a top brace they would bow to the point they would fail. If you ever order a custom, be sure to ask them to build it so it will not bow. It will cost more for thicker material.

marlinmon · May 22, 2019

Acrylic is more viscoelastic than plate glass. It can change shape. So can glass, but at a much much slower rate - look at glass in those churches that are centuries old.

sofaknlo · May 22, 2019

how much is too much tho? i put a level up to it and dang its bowin.

Aquavaj · May 23, 2019

I had a custom 47g rimless acrylic tank made with 3/4" panels and there was still some slight horizontal bowing. Tank was only 36" L and 16" high.
For a tank that big yeah there's going to considerable bowing.

Xanthurum · May 23, 2019

That is way too much bowing, not saying that the tank will fail but I used to work for an acrylic tank manufacturer and never saw any of our tanks bow like that.

Dom · May 23, 2019

sofaknlo said:
how much is too much tho? i put a level up to it and dang its bowin.

YIKES!

I have zero experience with acrylic tanks. But that would not leave me feeling comfortable.

Aquavaj · May 24, 2019

How thick is the acrylic and hows the top bracing look like?

Aardvark1134 · May 24, 2019

You should never get a rimless acrylic tank that is large. Large acrylic tanks should have euro bracing and a cross brace every 3 ft or so. Any large rimless braceless acrylic tank can fail. Even 1 million dollar ones have failed. Making acrylic thicker doesn't make it no longer acrylic. If you buy an acrylic tank buy one made with eurobracing and crossbracing. And yes I love acrylic tanks its all I will buy anymore.

vetteguy53081 · May 24, 2019

These are known to bow when there is a shift in weight due to not being level.
To level if off, I recommend a major water change ( to remove water), a 12 pack of good beer for three strong friends you will need and carefully tap shims under the tank where needed.
Your reward: A beer get together, a beneficial water change and a leveled tank

BestMomEver · May 24, 2019

We had a 500g, 8’ tank made of acrylic. Euro braced. Still bowed even though the acrylic was 3/4 - 1 inch thick (I don’t remember which). Scary, but it was fine. Some bowing will always happen, glass or acrylic. How much is acceptable? Don’t know.