Emergency substrate change

Hey,

I’m new to forums so here we go! I went away for school for 2 years leaving my 30 gal tank for someone else to watch. When I came back there was a thick layer of anaerobic material between the sand and blotches of red algae on the glass. When I moved my tank to my new house, all of this mess in the substrate surfaced and i got what I could out hoping it would be ok for my fish. Since I just moved I didn’t have a hospital tank set up and had no choice but to put them into the tank.

since, my beloved betta, 8 year old phantom tetra, and 6 harlequin rasboras died. Most of them heartbreakingly died of dropsy.

I have a 10 gal hospital tank that I set up 5 days ago (no substrate) and I put my functioning filter material into it to jump start it. ideally I want to move my fish into there temporarily and completely empty my entire 30 gal tank and start from scratch with 100% new substrate. What is everyone’s thoughts on this? Resources I have found said it would be fine, others say I would be removing beneficial bacteria risking a cycle reset and to substrate changes it in parts. I have tried removing the anaerobic bacteria in parts by stirring up very small sections at a time and keeping the vacuum right there to take in as much as possible immediately, but every time I do that another fish dies. if I have all of this horrible gram negative killing bacteria in my tank that is exposed to the water what am I really preserving at this point? The nitrates are also extremely high right now.

So… do I switch my fish into the hospital tank once’s numbers are good and gut my 30 gal tank? I feel at such a loss right now and debating in getting rid of my tank cause I’m doing more harm then good if I do gut it, I was going to do a gravel sand mix again because I like the gravel for the plants but the sand for the bottom feeders, what’s everyone’s thoughts on this? I’m scared of running into this mess again since that is what is currently in my tank.

my 30 gal currently has live plants: 5 Amano shrimp, 3 rummynose tetras, 6 black neon tetras, 1 harlequin rasbora, and 2 Cory cats. (I know my schooling numbers aren’t right, but the rasboras died, the rummynose were adopted, and I’m not adding more Corycats until I figure this out).

Last night I tested both tanks with the API freshwater test kit:

10 gal Hospital tank with no substrate or live plants:

• pH: 7.6
• Ammonia: 0.25
• Nitr: 0
• Nitrate: 5.0
• Temp: 78

30 gal Main planted tank with sand and gravel mix:

• pH: 7.8-8
• Ammonia: 0
• Nitrite: 0
• Nitrate: 40
• Temp: 81-82

Note, I have had this particular tank for 9 years and did a partial substrate change 2 years ago

 

Substrate looks fine to me. At 2 years that sand is very valuable, especially for plant growth.

How much were you feeding and how often are the water changes? A tank that has a lot of waste build up and no water changes can crash from big changes

Just slowly increase water changes and leave the substrate alone. Should probably significantly reduce feeding amounts too

 

Hi! Welcome to fishlore!, so sorry for your losses, but I don't think you need to give up! That might be one to many exclamation marks, but I mean it!
I dont know about sand substrate, I have read horror stories about anaerobic this and that. Is that the 30 gallon in the pictures? is it sand and gravel? how many inches of substrate?

I have smooth natural type gravel and my 12-year-old loaches have long uninhibited barbles.
I worry about a sand and gravel combo. Wouldnt the bottom feeders dig in there thinking they are safe, and end up banging into unexpected rocks?
If you had all smooth gravel I think that your cories would be fine.
If you had all sand you could add some kuhli loaches to stir up the sand.

In my experience, you can remove the entire substrate and not lose your cycle. I guess it helps if you already have a well-established cycle, and it sounds like you would, after more than 2 years. I have completely removed my substrate several times, most recently 6 months ago when my nephew poured an entire thing of food in my tank. I have never lost the cycle, but that doesnt mean you need to change yours.

40 ppm nitrate is not that high. It's a good idea to consider adjusting things to avoid it getting higher, but it is ok for most species.

 

Substrate looks fine to me. At 2 years that sand is very valuable, especially for plant growth.

How much were you feeding and how often are the water changes? A tank that has a lot of waste build up and no water changes can crash from big changes

Just slowly increase water changes and leave the substrate alone. Should probably significantly reduce feeding amounts too

I do 25% changes weekly, I barely loose fish never mind 8 within a month. But I will try feeding less, I have a couple of shy neon tetras that are smaller then the rest that avoid feeding around the others so I feed on both sides of the tank so maybe that’s causing issues. Thanks for the input!

Hi! Welcome to fishlore!, so sorry for your losses, but I don't think you need to give up! That might be one to many exclamation marks, but I mean it!
I dont know about sand substrate, I have read horror stories about anaerobic this and that. Is that the 30 gallon in the pictures? is it sand and gravel? how many inches of substrate?

I have smooth natural type gravel and my 12-year-old loaches have long uninhibited barbles.
I worry about a sand and gravel combo. Wouldnt the bottom feeders dig in there thinking they are safe, and end up banging into unexpected rocks?
If you had all smooth gravel I think that your cories would be fine.
If you had all sand you could add some kuhli loaches to stir up the sand.

In my experience, you can remove the entire substrate and not lose your cycle. I guess it helps if you already have a well-established cycle, and it sounds like you would, after more than 2 years. I have completely removed my substrate several times, most recently 6 months ago when my nephew poured an entire thing of food in my tank. I have never lost the cycle, but that doesnt mean you need to change yours.

40 ppm nitrate is not that high. It's a good idea to consider adjusting things to avoid it getting higher, but it is ok for most species.

It’s about 2.5 inches of substrate, which is where I’m worried the issues are coming from. But I have that much because I have a Amazon sword plant with a very large established root that refuses to stay in the substrate, and the gravel that is in there is smooth. I’ll look into the loaches though. Thank you very much for your input!

 

I do 25% changes weekly, I barely loose fish never mind 8 within a month. But I will try feeding less, I have a couple of shy neon tetras that are smaller then the rest that avoid feeding around the others so I feed on both sides of the tank so maybe that’s causing issues. Thanks for the input!

It’s about 2.5 inches of substrate, which is where I’m worried the issues are coming from. But I have that much because I have a Amazon sword plant with a very large established root that refuses to stay in the substrate, and the gravel that is in there is smooth. I’ll look into the loaches though. Thank you very much for your input!

If you do get kuhlies, get a lot of them, they are very social! Your plants look awesome! and you probably don't want to take advice from me, the plant killer. But I bought plastic canvas, and cut slots in it, and gently put that around my amozon sword bottom stems, then covered it with rocks, to hold them in place. I don't think that hurt the plants, I think It's my brown thumb.

 

If you do get kuhlies, get a lot of them, they are very social! Your plants look awesome! and you probably don't want to take advice from me, the plant killer. But I bought plastic canvas, and cut slots in it, and gently put that around my amozon sword bottom stems, then covered it with rocks, to hold them in place. I don't think that hurt the plants, I think It's my brown thumb.

Thank you!

 

This is the saddest thing I've ever heard. I know it might not sound right with nitrates only being 40, but my hypothesis is your tank had dreaded Old Tank Syndrome which is a spike of nitrates. This can be toxic to fish that aren't used to it. It sounds like your fish are happy and healthy and this is exactly why I say it's Old Tank Syndrome. The best thing you can do for this is LEAVE THE SUBSTRATE ALONE. Stirring it up is what spikes nitrates in the first place which aren't visible due to your giant sword absorbing much of it. But if you ever stir up that substrate again (accidental or purposeful), wait a few minutes then test the nitrate levels. I can guarantee they will be higher than you ever thought was possible. Luckily you have a sword to help keep that in check, but live plants won't instantly suck up excess nutrients. It takes them time to do so (albeit not much for some.)

I'm so sorry to hear about your fish. Bettas have been in my life for a decade and black phantom tetras are one of my favorite fish of all time. I've had Old Tank Syndrome when especially lazy in my 10-year fishkeeping journey and it isn't easy. Losing anyone, especially someone you love, is the worst thing about life. But realize they had a great life which an awesome person who cared about them. In our neighborhood if it isn't a dog, it doesn't matter...that's why I have an old gerbil, amphibians, fish, inverts, 3 lizards and 2 cats all of which are rescues.

You're great, Peachtree - don't bow to an issue easily fixed or avoided. You got this, and we got your back. Good luck friend. Feel free to ask for help anytime. Like I said, we've got your back

 

Thank you so much, the sympathy and support is appreciated.
If you suggest not to stir up the substrate and that this could be a case of old tank syndrome, is it safest to just remove all of it and start from scratch? Because I worry about the anaerobic bacteria that sits in the under layer.

 

It's not OTS, in the freshwater sense of the word and condition,
the pH is too high for that to have happened. the tank has had water changes, what it hasn't had is substrate disturbance for a long time, Maybe TDS is high and messing with the substrate with waterchanging is now lowering the TDS/ increasing the TDS, (not sure which really).
This is going to shock the fish, and mess with their osmosis. something they acclimated to slowly over a long period of time and being released in bumps in short periods of time. I think this is what's going on and why each time you mess with it, someone winds up with dropsy and retaining too much fluid build up.

if it's OTS, it would be that "saltwater OTS" where they have corals live rock and live sand, they can't clean under and everything collects there for years to come and haunt you later, bacteria and detritus buildup, and then popping off and making things nasty for the fish in short bursts, which takes like a decade to happen if left to it's own devices, but if you went in and messed with the substrate after just a couple years, those releases can be a problem.
People get scared to disturb the bottom regularly kick up the sand and cloud the water, so they don't. they'd prefer clean clear water.
But if you did saltwater and did nano or pico, this wouldn't fly at all. In short order it would head over to that "saltwater OTS" condition. where the substrate is full of junk and releasing and the more it gets messed with the bigger the releases.

So anyways, this is likely detritus and bacteria and aTDS shift as this stuff gets released causing fluid retention in the fish, one here, one there, it's really not the stuff that you can see that's the problem, it's the invisible stuff that releases that you can't see that cause the issue.

What I would do, remove the filter and water to the 10g, and move all animals out to the 10g. change out the substrate and clean up the 30g, spend a week reacclimating the fish to the clean tank slowly, small water changes at a time. from the 30g to the 10 g and dumping the water from the 10g as you do it,
Ideally two cycled tanks/filters would be better and a smoother transition than moving a filter back and forth. I think as long as you remove the animals from the releases as you mess with the substrate, they should be fine. but I'd still take the water they are used tobeing in and change like a half gallon to a gallon every day and ramp that up towards day 7 to larger changes so both tanks are close to in line with each other, Oh and use heaters so you can set the temps the same also, the less drastic change the better, they aren't used to things changing much over the last couple years. they have to be acclimated to water quality changing and improving, they had plenty of time to adjust to it getting worse slowly, it works both ways.

 

Thank you so much, the sympathy and support is appreciated.
If you suggest not to stir up the substrate and that this could be a case of old tank syndrome, is it safest to just remove all of it and start from scratch? Because I worry about the anaerobic bacteria that sits in the under layer.

Just water change and feed less and the nitrate will be processed by bacteria/plants in the tank. No need to replace everything

Should probably check the KH of the water too. When KH is depleted small changes can crash the tank.

 

Just water change and feed less and the nitrate will be processed by bacteria/plants in the tank. No need to replace everything

Should probably check the KH of the water too. When KH is depleted small changes can crash the tank.

Just water change and feed less and the nitrate will be processed by bacteria/plants in the tank. No need to replace everything

Should probably check the KH of the water too. When KH is depleted small changes can crash the tank.

Thank you so much!