Very Concerned, hopefully unfounded

[Fink]

So I'm in the early stages of a 90g setup that I bought used. Everything was going super well until i started cleaning the tank with a mag float the other day. The tank wobbles a little bit when I scrub front to back with the mag float. Is this normal?

For pictures, you can check out the build thread

Build Thread - My biggest tank yet 90g

I picked up a setup a few weeks ago from Facebook marketplace. It came with a tank/stand/sump/light. Unfortunately it was missing most of the plumbing... I had to wait a few weeks to get a local guy that used to run our only saltwater aquarium store (he is out of business now) come help me do...

www.reef2reef.com

If this is something to be concerned about, do I need to drain the tank and get a new stand, or can I shore up the existing structure?

Thanks!

 

[driftin]

Is the tank wobbling on the stand, or is the stand wobbling on the floor?

 

[dbowman5]

I hope there is no problem, theoretically you could use your other hand to hold the tank against the push of the scraper. the tank might be a little top heavy which might be the source of the movement. was there any sign of discoloration or puffiness in the stand that might mean weakness? any gaps of the panels? the stand looks like it was built to hold the tank. if it is in good condition it should support the aquarium as designed. i have 75's and they don't wobble. maybe you are stronger than me. good luck! maybe post the brand name of the combo to see if the particular stand does that.

 

[Reefing_addiction]

So I personally would buy or build a new stand. Check my build thread I built my own. I didn’t add doors yet on mine or cover it in anyway other than the top where the tank sits. It’s probably the sturdiest thing ever.
It looks like you have something sitting underneath you stand? This also may be the cause of your wobble.

 

[KrisReef]

Wobbling tanks do not sound good. I think you want to shim the stand to make the tank sit as level as possible. I'm not an engineer but I understand a little about acceleration and seam stability and glass surface stress.

 

[driftin]

To follow up on my question - you can shim the bottom of the stand, if it's wobbling on the floor. It's not uncommon for floors to not be perfectly flat. That's not a big deal IMO. But if the tank is not flat on the stand, that's a problem and you don't want to use shims there (potential to point load the bottom of the tank or frame). If that's where the wobble is, I'd drain it and add foam between, or get a new stand depending on how big the gap is.

 

[Gablami]

Agreed, that a wobbling tank is a serious issue. Assuming it is the stand and uneven flooring, you should shim the stand as stated above. But while you do this, the goal is not only to have a stable tank, it’s also to aim for a level tank. So get a long level and make sure that the tank is level as well.

 

[vetteguy53081]

Concerned - Yes
Is stand wood or metal?
If metal- look at the welds and if wood, uneven floor or joists.
Can require shimming as mentioned or bracing of the stand.

 

[piranhaman00]

Does it wobble or vibrate?

MY 180 metal stand vibrates when I clean with mag float as well. Everything is level. If it wobbles around its not even.

 

[TriggerFinger]

My 90g tank/stand doesn’t sway/wiggle/jiggle/wobble even with my 160lb self leaning on it, which happens every time I work in the tank. Definitely need to shim the stand to make it level and solid or build a new one. If you have kids or pets at risk of running into it, it could be a disaster.

 

[Fink]

Thanks for all of the follow up!

The wobble is the stand itself moving, like the joints in the wood are a little loose rather than a rocking back and forth that most people are suggesting. Everything is level, but there is just a little wiggle in the wood when I'm using the scraper. Better to catch it early before the tank is established with Coral I guess. The stand seemed really solid when I was moving it, but I guess 90g of water is a bit more taxing than being moved.....

@dyerrm I hadn't noticed that before, but I think it is swelling in the wood floor of the stand. The wood there is thicker than the black veneer that covers it. Previous owner may have had a spill down there at some point.
@piranhaman00 vibration may be a better way to describe what I'm talking about.
@vetteguy53081 When I put a level on the stand it was good, i'll do it again when I get home to see if adding water changed anything

Sucks that I really like the look of this stand, and I have no idea on brand name, so I'll just have to find something new I guess.

 

[KrisReef]

Thanks for all of the follow up!

The wobble is the stand itself moving, like the joints in the wood are a little loose rather than a rocking back and forth that most people are suggesting. Everything is level, but there is just a little wiggle in the wood when I'm using the scraper. Better to catch it early before the tank is established with Coral I guess. The stand seemed really solid when I was moving it, but I guess 90g of water is a bit more taxing than being moved.....

@dyerrm I hadn't noticed that before, but I think it is swelling in the wood floor of the stand. The wood there is thicker than the black veneer that covers it. Previous owner may have had a spill down there at some point.
@piranhaman00 vibration may be a better way to describe what I'm talking about.
@vetteguy53081 When I put a level on the stand it was good, i'll do it again when I get home to see if adding water changed anything

Sucks that I really like the look of this stand, and I have no idea on brand name, so I'll just have to find something new I guess.

With this information, in the short term you might want to consider bracing the stand on the inside (I'm thinking earthquake retrofit-blocks in the corner(s) where you can to stop the movement. A good retrofit might give you a lot of time without having to swap stands immediately?