Tank stand.

[workhz]

Where there’s a will there’s a way. It could probably be supported with reinforcements. The drawers are in the way but you could support the section under the drawers as the vertical pieces between the drawers would help support the top. Just figure where all the weight is going and make sure you don’t have a weak link somewhere.
Above the drawers you could probably screw in a couple of pieces of wood to support the sides better.

 

[LeftyReefer]

Depends if OP wants to retain the function of the drawers or not. If not, just pull out the drawers and only use the drawer faces as a façade, and then add supports internally. If its only the aesthetics of the stand you want to maintain, then I'm sure it can be done. if you also want to maintain the function of the drawers, it will be difficult if not impossible.

 

[Hugh Mann]

Hard no.
Saltwater weighs approximately 8.6lb/gallon, or 258lb or about 117kg. Some water will be displaced by sand and rock, which is much heavier than water. Plus the weight of equipment, filters, etc.

Probably fine for short term, but long term, I would not trust it without reinforcement.

 

[Soren]

Do you have any more pictures, especially from different angles such as side/top/back/bottom/inside views?
This could easily be modified to hold a 30-gallon tank.
If the legs are solid oak, all you would need to do is add a frame on top to distribute load to the legs which should easily be strong enough to support a 30-gallon tank.

If you can share more details about the stand structure, I can explain more about modifications to ensure enough strength.

Yes, manufacturers will state a load limit below true limit (called safety factor), but that is there for a reason and you do not want to intentionally exceed rating without knowing the full details of the design and support structure.

 

[Reef.]

Do you have any more pictures, especially from different angles such as side/top/back/bottom/inside views?
This could easily be modified to hold a 30-gallon tank.
If the legs are solid oak, all you would need to do is add a frame on top to distribute load to the legs which should easily be strong enough to support a 30-gallon tank.

If you can share more details about the stand structure, I can explain more about modifications to ensure enough strength.

Yes, manufacturers will state a load limit below true limit (called safety factor), but that is there for a reason and you do not want to intentionally exceed rating without knowing the full details of the design and support structure.

Would appreciate any help as I would prefer to use a non aquarium stand if possible.

sideboard is 130cm long and 40 wife, IM 30l 90cm long and 38cm wide.

 

[Soren]

Would appreciate any help as I would prefer to use a non aquarium stand if possible.

sideboard is 130cm long and 40 wife, IM 30l 90cm long and 38cm wide.

How handy are you with basic woodworking to modify the stand? I can think of a few modifications that would likely make this strong enough to support a 30-gallon tank.
For clarification, stand top is 130cm (51.18in) long flat-side to flat-side and 40cm (15.75in) front-to-back? ...and tank footprint dimensions are 90cm (35.43in) long by 38cm (14.96in) front-to-back?

Are you planning to keep tank centered on the stand? With the extra width of the stand (130cm compared to tank 90cm), loading will be in the center of the stand rather than over the legs. This is not ideal, so you would want to disperse the load onto the legs as directly as possible. If you aligned the tank on one end of the stand, part of the tank could be directly over two legs (best-case for strength), but the distance from the other end to the other legs would be maximized (which is worst-case for strength). With the right modifications, though, this is probably a non-issue and the tank can be placed anywhere atop the stand.

It appears that the corner legs are solid oak, so these should be your primary support points, ideally.

The first modification to ensure strength would be to add plywood across the top to increase thickness and support strength while also distributing a bit of the load out to the legs instead of center of the top board. Without extra bracing, this would not be ideal, since you would need thick plywood to avoid bowing. Adding this on top of the full-frame option below would probably be the most ideal situation for added strength.

Spoiler: One minimal solution, though not ideal

Another idea I have would be to add a standard construction 2x4 (1-1/2"X3-1/2") pine board or oak/hardwood 1x4 (3/4"X3.5") across the back of the stand that fastens directly to the back of the back legs. This board would be supported by shear only on the screws, which is definitely not recommended for general stand construction but would be sufficient enough for your case where you just need a bit of added strength. In addition to the back brace at the top, you could also add a diagonal under this brace from one side to the bottom of the stand on the opposite leg on the back. This would add some strength, but it also assumes a lot about the weight-bearing integrity of the furniture construction...
See blue boards:

A better solution would be to create a full frame atop the corner legs by fastening a 2x6 across the top of each end of the stand and run 2x4's, 2x6's, or 2x8's across the top to mount and support directly from the furniture main legs. This would be directly visible and would need to be stained and varnished to look like finished furniture. I am quite confident the added strength here would be enough for a 30-gallon tank if you screw through the side 2x6's directly into the main legs on the corners (pre-drill the holes to avoid splitting the wood). I would also recommend using both wood glue and screws at all joints for added strength. If you can find a good way to do so, you could fill in the rounded corners of the stand to add more support directly to the top of the leg. This is ideal so the wood takes the loading directly instead of the screws supporting in shear. More strength is added if you cover the entire top with lumber as shown below in blue and a surface of plywood could be added on top of this for even more surety and a better top finish:

If you have any questions or need further explanation, just ask.

 

[Reef.]

Wow cheers for that, looks like it's possible.

My diy skills are limited but I'm good at following instructions.

found this list of materials used, someone asked the question on the company's website and got this reply, would this change your advice?...

TOP FACE
Front top rail Solid wood
Top panel MDF veneer
side under top panel Solid wood
FRONT FACE
Front Legs Solid wood
Front rail (Horizontal) Solid wood
Front rail (Horizontal) Solid wood
Front rail (vertical) Solid wood
SIDE FACE
Top side rail Solid wood
Bottom side rail Solid wood
Side Panel MDF veneer
BACK FACE
Back legs Solid wood
back rail (Horizontal) Solid wood
back rail (Vertical) Solid wood
Back Panel MDF veneer
MIDDLE PANEL
Middle panel (vertical) MDF veneer
LEFT BOTTOM PART
Left Bottom Panel MDF veneer
Support Under Bottom Panel Solid wood
Support Under Bottom Panel Solid wood
RIGHT BOTTOM PART
Right Bottom Panel MDF veneer
Support Under Bottom Panel Solid wood
Support Under Bottom Panel Solid wood
DOOR FRAME
Door rail (Vertical) Solid wood
Door rail (Horizontal) Solid wood
Door panel MDF veneer
Wood of door hinge Solid wood
WOODEN RUNNER
Wooden Slidding for Drawers Solid wood
Wooden Slidding for Drawers Solid wood
Wooden Block Solid wood
Middle Wooden Slidding for Drawers Solid wood
Middle Wooden Slidding for Drawers Solid wood
Wooden Block Solid wood
DRAWERS
Front of Drawer Solid wood
Side of Drawer Solid wood
Back of drawer Solid wood
Bottom Panel of Drawer MDF veneer
corner Under Bottom Panel of Drawers Solid wood
ADJUSTABLE LARGE SHELF
Adjustable large shelf frame Solid wood
Adjustable large shelf frame Solid wood
Adjustable large shelf panel MDF veneer
Support large shelf panel Solid wood
ADJUSTABLE SMALL SHELF
Adjustable large shelf frame Solid wood
Adjustable large shelf frame Solid wood
Adjustable large shelf panel MDF veneer

 

[nereefpat]

If the top and legs are solid wood, you can beef up the stand from the inside using 1x4s or 2x4s (1xs are plenty strong). The goal will be to transfer the weight all the way from the top of the stand to the floor using lumber. You should use screws and/or glue, but if built properly those aren't supporting any weight.

I don't love MDF for aquarium stands, since it's a fiberboard and isn't the best for wet locations.

 

[Soren]

Wow cheers for that, looks like it's possible.

My diy skills are limited but I'm good at following instructions.

found this list of materials used, someone asked the question on the company's website and got this reply, would this change your advice?...

TOP FACE
Front top rail Solid wood
Top panel MDF veneer
side under top panel Solid wood
FRONT FACE
Front Legs Solid wood
Front rail (Horizontal) Solid wood
Front rail (Horizontal) Solid wood
Front rail (vertical) Solid wood
SIDE FACE
Top side rail Solid wood
Bottom side rail Solid wood
Side Panel MDF veneer
BACK FACE
Back legs Solid wood
back rail (Horizontal) Solid wood
back rail (Vertical) Solid wood
Back Panel MDF veneer
MIDDLE PANEL
Middle panel (vertical) MDF veneer
LEFT BOTTOM PART
Left Bottom Panel MDF veneer
Support Under Bottom Panel Solid wood
Support Under Bottom Panel Solid wood
RIGHT BOTTOM PART
Right Bottom Panel MDF veneer
Support Under Bottom Panel Solid wood
Support Under Bottom Panel Solid wood
DOOR FRAME
Door rail (Vertical) Solid wood
Door rail (Horizontal) Solid wood
Door panel MDF veneer
Wood of door hinge Solid wood
WOODEN RUNNER
Wooden Slidding for Drawers Solid wood
Wooden Slidding for Drawers Solid wood
Wooden Block Solid wood
Middle Wooden Slidding for Drawers Solid wood
Middle Wooden Slidding for Drawers Solid wood
Wooden Block Solid wood
DRAWERS
Front of Drawer Solid wood
Side of Drawer Solid wood
Back of drawer Solid wood
Bottom Panel of Drawer MDF veneer
corner Under Bottom Panel of Drawers Solid wood
ADJUSTABLE LARGE SHELF
Adjustable large shelf frame Solid wood
Adjustable large shelf frame Solid wood
Adjustable large shelf panel MDF veneer
Support large shelf panel Solid wood
ADJUSTABLE SMALL SHELF
Adjustable large shelf frame Solid wood
Adjustable large shelf frame Solid wood
Adjustable large shelf panel MDF veneer

I have not looked through this thoroughly, but I do not see anything that goes against my initial assumptions or would change my mind on my recommendation.

I agree with @nereefpat about bracing from the inside as a possibility, but this may be challenging to support under the tank all the way to the floor since you may have to cut through the bottom of the cabinet in order to run lumber straight through. Again, you would probably achieve internal support by tying into the solid legs.

+1 @nereefpat to support with lumber from top of stand all the way to the floor, screws and glue are used to hold the wood together but should not be providing primary weight support, and MDF is not ideal for wet circumstances since it can expand and break apart if it gets too wet for too long or too often. The MDF is mostly a question of appearance, though, since it is not and should never be used as primary support for an aquarium due to the above concern. Solid oak legs should provide sufficient support regardless of the state of the MDF (though the MDF may be used in the case of this stand to provide resistance to twist and could be a problem if it falls apart, to remediate this issue you could add diagonal bracing boards on the back of the stand or inside the sides to keep the stand or legs from twisting).

I can try to give specific instructions on my recommendations if necessary since the load limit of the furniture is not far below actual load, but I do not want to assume risk for the use of this stand without being able to see it in person. To ensure support, you could add weights to the stand exceeding expected weight of aquarium to make sure the stand is strong enough after reinforcing before risking the aquarium.

Edit: Also, I would recommend sealing the entire stand after modifications with a waterproofing varnish to help prevent water damage.

 

[Reefer_punk]

50g happily standing in a sideboard. Just make sure the wood is strong and not that pressed carton garbage

 

[rioreef]

Wow cheers for that, looks like it's possible.

My diy skills are limited but I'm good at following instructions.

found this list of materials used, someone asked the question on the company's website and got this reply, would this change your advice?...

Even if you took out those rounded corners to support a top, looks like all weight is on just the four corner pieces. The side panels provide no support.

Ask yourself this...
What's your insurance deductible if it fails? Weigh that and damage/repairs against cost of a proper stand.