Gravel change, BIG mistake??
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hgwerner Offline
#1 Posted : 09 September 2009 13:33:42(UTC)
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<p>I recently, after doing research, decided to change out the gravel in my aquarium from a natrual brown to a slightly finer Roman black gravel. Everything went fine for about a day, I left a small mesh bag filled with the old gravel to help the transition. I also added some plants on the same day. The next day I found the fish all gasping for air on the surface. At that time I had:</p> <p>6 x Male guppies</p> <p>4 x female guppies</p> <p>6 x guppy fry</p> <p>2 x electric blue rams</p> <p>2 x raspbora</p> <p>2 x otocinuclus</p> <p>1 x cray fish</p> <p>&nbsp;</p> <p>My tank setup is:</p> <p>Juwel Rekord 60 (63 liters)</p> <p>&nbsp;</p> <p>Water quality tests (varied over time) Last tests:</p> <p>pH - 7.2</p> <p>Amonia - 0</p> <p>Nitrite - 0.25</p> <p>Nitrate - 5.0</p> <p>&nbsp;</p> <p>Both my rams have now died and the guppies are flashing, rubbing against all kinds of surfaces. Is this due to me changing the gravel, causing the tank to re-cycle? or could there be a contaminant? Any help would be greatly appreciated!</p>
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Bluedave Offline
#2 Posted : 09 September 2009 13:52:39(UTC)
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What did you do with your filter media (the sponges in the filter)? Changing the gravel does not generally give you any problems. If the sponges were left to dry out or you added new water without dechlorinator or washed the sponges in tap water then you may have killed the bacteria in the filter.

Some sort of re-cycling(!) appears to have taken place with the presence of nitrites in the water. All you can really do now is to carry out daily 10% water changes and monitor the water parameters until they are normal again. Sounds like the worst of it is over, so hopefully you won't suffer any more losses.
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hgwerner Offline
#3 Posted : 09 September 2009 14:08:19(UTC)
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I didnt touch the filter media, except the top white filter, which needed replacing anyway. I dechlorinated the water, and the filter shouldnt have dried out in the 5 minutes it took me to change the gravel. I only removed a quarter of the water during the process. So you think my other fish should live through the cycling? I was worried it might be a parasite or toxin. Thanks for the quick reply. Smile

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Bluedave Offline
#4 Posted : 09 September 2009 15:57:07(UTC)
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Well, you did everything by the book so the filter bacteria should be fine and dandy! While helpful bacteria are contained on the gravel you are not overly stocked so that that should make a difference. It may have been something in the old gravel that reared it's ugly head when you disturbed it. You may have had some anearobic areas in the substrate that were disturbed and released hydrogen sulphide - this would account for the fish gasping at the top? This could also cause your tank to recycle.

I'm assuming this happened a few days ago? If so then I think you have been through the ammonia stage of the cycle and are now running through the nitrite stage. This means you are through the worst of it. As before small daily water changes to give the remaining fish a chance.

Good luck with it.
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hgwerner Offline
#5 Posted : 09 September 2009 19:57:13(UTC)
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Thank you for the suggestion about the hydrogen sulphide. That deffinatly sounds like a possibility. On a suggestion by the my local aquarium store I have added Tetra SafeStart this morning in order to help along the cycling process. My most recent water test results are as follows:

pH - 7.2

Amonia - 0

Nitrite - 0

Nitrate - 0

Is it normal for all bacteria to have dissapeared? Also dispite the lack of nitrite and amonia, the fish are still gasping for air at the surface... is this just part of the cycling process? I dont remember this happening when I started the tank.

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imustbedreamin Offline
#6 Posted : 09 September 2009 20:50:57(UTC)

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did you wash the new substrate before it went in?

i would be concerned you are not getting a nitrate reading

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hgwerner Offline
#7 Posted : 09 September 2009 21:11:20(UTC)
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Yeah I washed the gravel. Although it didnt seem to need much rinsing, as not much residue came off it. Also when i filled the tank it seemed clean.

I double checked the Nitrate reading because I thought I might have made a mistake. But got the same reading, 0. I honestly can't explain that...

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ferox Offline
#8 Posted : 09 September 2009 23:05:25(UTC)
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I can't think that the gravel change could have triggered recycling if the fish were gasping at the surface the very day after  - not enough time for ammonia to accumulate in the water and no ammonia showing up in tests so soon after (I'm assuming the tests results you posted were obtained very soon after the gravel change). But the presence of nitrite does suggest the tank was at least a week or two into the process of cycling (or recycling) already at the time of the gravel change. Had the tank been disturbed in any way within the month prior to this?

If Hydrogen sulphide was released from the old gravel in quantities sufficient to damage the fish I'd guess you'd have almost certainly been able to smell rotten eggs when you removed it, do you remember that?

 

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ferox Offline
#9 Posted : 09 September 2009 23:10:13(UTC)
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Forgetting my manners btw,

Welcome to Fishcrazy! [wave]

Garden shed full of tanks (tropicals) and a pond.

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hgwerner Offline
#10 Posted : 09 September 2009 23:17:06(UTC)
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Thanks for the welcome. I don't remember smelling rotten eggs. However I did see a slight layer of white/grey film on the sirface yesterday, but this has mostly gone away now. I didnt disrupt the tank much in the last month, except for taking my two ornaments out to remove excess algae. I tested the water right after the gravel change and had safe values: pH - 7.8 (slightly higher than normal but this dropped) Amonia - 0 Nitrite - 0 Nitrate - 20 It wasnt until the next morning that I noticed the fish were unhappy. I'm worried though as I have no idea as to what exactly is happening with my tank, and I have to leave for a week this friday. I'm afriad I'll come back to find all of them dead. [Sad]
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ferox Offline
#11 Posted : 09 September 2009 23:37:52(UTC)
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Maybe not hydrogen sulphide then, that really does stink, you would have noticed it I'm sure. And odd that nitrite suddenly appeared but you never detected any ammonia throughout the time. What's the timescale of all this, how long ago was the gravel change?

Other things that occur to me;

-You added plants at the same time, I wonder if anything might have come in on them.

-A pH change of 0.6 over a short space of time is pretty significant, I wonder what caused that and whether it may have hurt the fish.

-The fish are still gasping at the surface suggesting amongst other things gill damage (ammonia may have caused this if there had been any) or there's low oxygen in the water. If you have an airpump it might be worth using with an airstone to see if that gives them relief.

What's your water temperature btw?

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hgwerner Offline
#12 Posted : 09 September 2009 23:44:31(UTC)
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I changed the gravel monday early afternoon. So it literally only has been a couple of days. I had considered the plants as well, but they look fine. I am curious too as to what caused the pH change. As for the lack of oxygen, I didnt think that could be it, as I have about 5 to 6 plants in the tank which should be producing plenty of oxygen. I keep my tank at a constant 27c. Annoyingly I dont own an airpump or air stone, as this tends to harm the plants, so I cant really test that out at the moment.
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ferox Offline
#13 Posted : 10 September 2009 00:01:46(UTC)
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So everything has happened on a very short timescale indeed.

Rapid pH change, Nitrate gone from 20 to 5 to 0 in 2 days, grey scum/film on water surface.

Clutching at straws here really, but I wonder if there's some sort of chemical got in there which has reacted with nitrate to form an insoluble compound which floated on the surface and which is either toxic to fish or has removed oxygen from the water. I don't know of anything that would do that and never heard of anything similar happening but putting all the evidence together that's the best I can come up with.

Plants only produce oxygen in the presence of good light, in the dark they consume oxygen. In reality they'll actually make very little impact on the oxygen level in the water. If you reposition your filter so that the output is causing as much agitation at the surface as possible this should help oxygenation. I guess that the surface isn't being agitated much if a film has been able to form.

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hgwerner Offline
#14 Posted : 10 September 2009 10:14:13(UTC)
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Well, I dont want to speak too soon, but it seems as though everything sorted itself out. Sort of at least. The fish are all back to their regular selves and there doesnt seem to be any more film on the surface. Water tests were as follows: pH - 7.2 Amonia - 0 Nitrate - 0 Nitrite - 0 Can I stop worrying?
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ferox Offline
#15 Posted : 10 September 2009 23:10:03(UTC)
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Very good news, just a pity you had to end up losing fish in the process. Must have been low oxygen that was affecting the fish, seems like there wasn't anything that caused lasting damage? Still bamboozled by the drop in nitrate though.

At least it looks like you don't have to worry about going away for a week any more.

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hgwerner Offline
#16 Posted : 10 September 2009 23:21:10(UTC)
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I think I might have a theory as to where the lack of oxygen came into play. When I got my crayfish, I blocked off the two holes in the back of my tank. Yesterday, I left the top of my tank open, in hopes of clearing away any hydrogen sulfide, if that was indeed the case, and the fish got better. Today I finished decorating my tank, with two retaining walls to create different levels. After adding a tiny bit more gravel the fish were back to the surface, not quite as bad as before but still. I have now removed the wood that was blocking the holes and have glued metal bars over the opening, so as to keep my crayfish from escaping whilst still allowing for ventilation. Maybe I should get an airstone to run during the night? I dont want to run it all the time due to the live plants. Now I just have to figure out why my nitrate levels are still at zero. Maybe my filter needs cleaning? Thanks for all your help. Deffinatly helped me get some sleep at night.
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ferox Offline
#17 Posted : 10 September 2009 23:44:35(UTC)
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Could be right about the oxygen if the lid was effectively sealed - but remember fish will stay alive in the plastic bag you buy them in for quite a long time with a tiny airgap at the top, and fish are shipped in bags like that from the other side of the world (albeit with pure oxygen rather than air) so I'd think he lid would have had to have been sealed for a long time before it would result in oxygen starvation.

I use airstones in all my planted tanks because I use air driven undergravel filters. The plants are fine, just like those you see growing in river pools below waterfalls. There's no good reason I can see that you shouldn't run an airstone 24 hours, and at least one good reason why you should!

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Bluedave Offline
#18 Posted : 11 September 2009 08:28:15(UTC)
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The only downside to airstones is that they are supposed to oxygenate the water which 'gases off' CO2. In my opinion it doesn't make a massive difference and as long as you have enough CO2 in the tank the plants will be fine. Gaseous exchange at the surface is more important. Where it does make a big difference is with heavily planted tanks that you are adding CO2 into. Here an airstone doesn't make sense as you are just wasting money!
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