The screws/hardware thatís holding the piece of furniture together are under enormous amounts of stress.
A 55G tank filled with JUST plain water is about 625lbs
Based on your 1 photo of your entire setup.....
- ∑ The two - 5G or 10G HOB filters youíre using = 10lbs total
- ∑ Random ornaments & 2 airstones = 4lbs
- ∑ Hood & lighting & heater = 10lbs
Fortunately there is no gravel because that would increase the weight by an additional 75-100lbs.
Total weight is about roughly 660lbs
(Itís always better to overestimate)
Hard to judge the stability & strength of a piece of furniture based on 1 picture of the exterior of the cabinet/stand.
The type of wood & hardware used throughout the piece is how you determine the overall strength of the piece.
When you remove/siphon....
- 10G of water = 90lbs
- 15G of water = 180lbs
A difference of 90lbs shouldn't cause creaking. That noise alone should indicate that something is NOT secure.
It could be as simple as the stand not being LEVEL. (24" level should be no more than $10)
Iím not sure what else you store inside the stand, but if you ever ACCIDENTALLY lean on the tank, that additional weight alone could turn that creaking into a CRACK & the worst case scenario will follow.
- If you decide you want to reinforce the stand, the 55G tank should be completely drained & removed FIRST.
- Get a level & someone handy who can use a miter saw to trim the pieces of wood to fit your stand.
- Pre-drill your holes, use quality SCREWS instead of nails.
- Use at least 4 corner brackets.
Highly recommend you get someone skilled in carpentry to look at the stand this weekend.
Hopefully I'm completely wrong, but when it comes to potential water damage, it's always better to be safe.
You may want to contact the saltwater tank mods... ReefingMadness & Tazman & see what their opinion is.
Best of luck.