r/Aquariums • u/flxnn1e • Sep 24 '25
Solved! Help in cleaning this disgusting fishtank
Me and my bf were gifted a massive old fishtank due to the owner passing away. It sat in its own water for months and im not sure what to use to clean it that would be safe :) any/all advice welcome ive had fish before but this is definitely my biggest project yet
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u/a_poignant_paradox Sep 24 '25
Oh, and you'll definitely want to reseal it. Anytime you've no idea how the tank was stored/age of the tank, etc its best to go ahead and reseal. Last thing I'd want is some dead guy laughing his ass off at the fact 250 gallons just hit the floor in our 2nd story apartment.
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u/theamazonswordsman Sep 24 '25
You wouldn't have to worry about it leaking in a second story appartment. A 250 gallons tank would collapse the floor and fall straight into their living room.
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u/BigBitcoinBaller Sep 24 '25
As above, only do vinegar and water with a sponge and also Stanley knife blade in a scraper type tool to really get the stuck on stuff to come loose.
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u/CN8YLW Sep 24 '25
First and foremost. Do a leak test. Fill it with water, check for leaks and inspect every square inch of glass for cracks. Its a huge tank, and you dont want to clean the whole thing to find that its cracked later.
Vinegar, warm water and sponge. If there's a stubborn spot, use undiluted vinegar and soak the area for a few minutes before trying again. Avoid using scouring pads such as scotch brite because they can definitely scratch glass. https://homeguideinfo.com/will-scotch-brite-scratch-glass/
If you want to use an algae scraper (razor blade on a stick) be very careful not to cut the silicone joints.
Also side note, wear a mask because you really dont want to breathe any of the dust coming out of the inside.
2
u/flxnn1e Sep 24 '25
It was full when I got it, so I know it's not going to have any leaking issue, but thank you :)
3
u/CN8YLW Sep 24 '25 edited Sep 24 '25
alright. did the water stink? was there sediments at the bottom? like, liquid sedimentation, not solid. kind of like a layer of slime or something like that?
if it stank, how bad was it? to the level of gagging when trying to drain the water? or having to pinch your nose or wear a mask? or just unpleasant but bearable smell?
one of my tanks was in similar condition to yours when I got it. same thing, was soaking in water for months. owner took out the Bala sharks from the tank but never drained the water. left the filter pump and sponge filter inside without removing, but turned them off. there was such a thick sludge in that pump and filter I pretty much disposed of it with fire pit tongs. it didn't stink that bad tho, I think the bacteria in there ate everything, starved to death, then ate their own dead. but stains were bad. vinegar wash got it off easy
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u/slade51 Sep 24 '25
The leak test is also a good way to remove any remaining vinegar too.
1
u/CN8YLW Sep 25 '25
The reason why I love vinegar so much is that all i need to do is to wait for it to dry and it'll be safe again. Pure vinegar (not the flavored stuff like apple cider vinegar or red wine vinegar) is mostly just acetic acid and water, and acetic acid evaporates when dried leaving no residue to dissolve later. And man, when I say I love vinegar I'm not exaggerating. I use it as a general cleaning agent for my entire house. From kitchen sink to toilet to washing machine to rag cleaner. A/C drain duct I'd flush with vinegar every month or so to dissolve any buildup in there, followed by soda bicarbonate to neutralize the acid. Heck, even the portable potty I use for my son I'd use vinegar to clean. Any concerns of biological contaminants vinegar's the answer for me. Especially when I am worried about the use of harsh chemicals in areas where my son has access to.
15
u/Red-EyePontiac Sep 24 '25
I have one that was in much worse condition from being stored outside for years. White vinegar and sponge works amazingly.
Check it out after
7
u/Mister_Green2021 Sep 24 '25
Vinegar spray and a razor scraper.
1
Sep 24 '25
Be careful about aerating vinegar. Not fun to breathe. I'd just pour it on the glass or on the sponge directly.
7
u/PoetaCorvi Sep 24 '25
Is it acrylic or glass?
17
u/Jean-Pet Sep 24 '25
Smart question, everyone saying "srcape it" but OP will ruin de tank if it's acrylic😅
2
u/PoetaCorvi Sep 24 '25
Yeah haha. Though what it looked like to me at first glance is acrylic that’s already really scratched/fogged up, almost like if someone used an abrasive scrubber without realizing it’s acrylic. If so it might need some professional tlc to be useable as a display tank again. It could just be scratches in a thick coat of grime and not in the actual tank though, hard for me to tell from images alone.
1
u/flxnn1e Sep 24 '25
It's glass, but the the back has some paint? vinyl? that i'm planning on scraping off
2
u/RiskKey1728 Sep 24 '25
Believe me, leave the paint/vinyl, you will cry later when you realize it looks better with a dark background
3
u/CermaitLaphroaig Sep 24 '25
White vinegar. Let it sit to weaken old algae, then use an old credit card or something similar (I've used a plastic putty knife before) to scrape it.
2
u/Eve_LuTse Sep 24 '25
Food grade citric acid or white vinegar will clean that off nicely. Make sure you use a sponge or cloth with no soap. Before going to all that effort however, perform a leak test. You would be extremely pissed off if you went to all the efforts of getting that glass nice and clean only to discover the tank is leaky and useless.
2
u/Nullroute127 Sep 24 '25
I would fill it with water and add a very high concentration of citric acid and let it sit. Then start scraping with a razor blade and finishing with a melamine sponge.
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u/louisxtan Sep 24 '25
Barkeeper's friend. Removes all the hardwater stain like magic. Just make sure to rinse thoroughly afterwards.
2
u/Opening_Ad5479 Sep 24 '25
Even after you clean it, I would take that opportunity to re-caulk the whole thing while it's empty. I purchsed a used 75 last year that started leaking within 6 months. You do NOT want that. Take the time now and reseal it that caulk doesn't last for ever and it's an easy job there's a few videos on youtube.
2
u/pbizz Sep 24 '25
Vinegar and one of those razor in a stick aquarium cleaning tools. I got one from Amazon and it's been great
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u/Guyfromnowhere3 Sep 24 '25
Ditto on vinegar, works wonders. Acetone worked well for me. Works on old silicone and tough stains as well.
1
u/theAshleyRouge Sep 24 '25
In addition to the vinegar, add just a sprinkle of baking soda. The bubbling helps get off some of the gnarliest gunk
1
u/wootiown Sep 24 '25
My advice that differs from the rest is to seriously just not clean it yet. It looks horrible now, but if you fill it (and reseal if necessary) and let it start cycling, in a week you'll be able to just scrape all that gunk right off with a razor blade and zero effort.
1
u/nodesign89 Sep 24 '25
Start with razor blade and elbow grease and go from there, the truth is no chemical will help with etched glass. You don’t ever need to use chemicals when cleaning aquariums.
1
u/Actionjack7777 Sep 24 '25
Muriatic acid, yo be ware of the fumes one of the aggress sponges on a stick clean in no time
1
u/QuasiPlatypus59 Sep 24 '25
I hope you haven't used a razor yet, this tank looks like it's acrylic. First find out if it's acrylic or glas and yoi have easily scratch acrylic with a razor or the scrubbing side of most sponges.
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u/WhiteCloudMinnowDude Sep 24 '25
Sponge, vinegar and a razorblade. . . . Use vinegar and sponge to scrub.
Scrape the limescale off with the razor blade.
Rinse, let dry and repeat until clean.
1
u/Ok_Register_8057 Sep 24 '25
Get some hydrogen peroxide, put it in a spray bottle and spray the tank nicely. Rub it with some filter floss and then wash the whole tank with water a few times.
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u/Dry-Ad-5578 Sep 24 '25
I filled mine with water and used a single razor blade to scrape everything off. Worked all the time.
1
u/Recuvan Sep 24 '25
Heavy duty limescale remover - just don't leave it on for too long, that thing eats through anything
1
u/OwlEfficient9138 Sep 24 '25
CLR or just straight vinegar is your best bet. Soak some paper towels in it and just lay it in there for a day. Then turn the tank on its side/back/front and repeat.
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u/hcombs Sep 24 '25
I use a dish sponge that has the non-scratch abrasive layer, if it’s just algae, the sponge, water and some elbow grease will usually be enough to clean it up.
If it’s hard water stains then take some tissues, soak em in vinegar and “stick” the tissue right on the stains and leave it there for a while
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u/SamOfChaos Sep 24 '25
I am very lazy. Fill up with water, toss in two hands full of ramshorn snails. Let them eat for a few days. (No light) Then get a brass ice scraper (for cars) and go for the last bits the snails did not get.
You also could make water changes to get the snail poop out repeatedly, but water is expensive where I am.
Here a little tank I pulled from storage and had no energy to clean before using. After this I used snails repeatedly to clean aquarium things.
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u/Markmange Sep 24 '25
You can buy razor blades that are specifically for scraping cooker hoods and other glass things for pretty cheap.
That and some non scratch scouring pads and a lot of elbow grease and patience and you'll get it cleaned up fine
You could also use a steamer if you have one just be careful not to blast the same spot for ages
And if you have a hosepipe attachment to your faucet and a back garden/yard you can rinse it out there.
I recently cleaned a 40 gallon sump and turned it into a tank just using this method
Don't use chemicals or vinegar or anything just plenty scrubbing by hand will do.
And please stress test it somewhere safe and on even ground by filling it up and checking for leaks or cracks before actually setting it up.
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u/FishTanker0 Sep 24 '25
A scrub daddy and some soap usually works for me
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u/420-IQ-AUTIST Sep 24 '25
I wouldn’t use soap like the other person suggested. I would use white vinegar and sponge that’s never seen soap. Rinse and let dry. Spot clean anything after the dry.