Total substrate change... the good, the bad, the ugly

[Scott]

I made a major change to my 55 gallon established (cycled and stocked with
15 various fish) tonight, and wonder about potential serious changes to
water chemistry that I wonder if anyone can answer. The gravel I was using
in the tank was quite large, around 1/4" in diameter and I noticed that a
lot of debris was making its way to the bottom of the gravel - IE when I
vacuumed the gravel I was getting a LOT of crap collecting deep in the
substrate. This concerned me because I feared anoxic layers developing in
the deeper layers of gravel and producing potentially toxic compounds.

So... I removed all of my fish - and saved about 25 gallons of the old tank
water - some in two 10 gallon tanks, and some in 5 gallon buckets. The fish
were moved to the two 10 gallon tanks, and the filters from 55 gallon tank
(two penguin 350b filters) were put on each of the 10 gallon tanks to keep
them running and preserve the biological media in the filters. Then I
totally changed the substrate in the 55 gallon tank to a more sand like
substrate. Kind of a trade-off between using very expensive flourite, and
using a small diameter gravel/sand. Eventually I would plant this tank with
some low-light plants. The gravel I used is pool filter sand, which claims
not to be chemically treated. I took the sand and rinsed it in an old
pillowcase to remove as much debris as possible.

End result now... my fish are ****ed at me and not feeding normally - but
could be expected from being netted twice in one night. Water is quite
clear. My big question is - the gravel does support a portion of the
bio-filtration. I removed a large portion of that bio-filtration, but I must
have removed a large bio-load on the tank with decomposing food, poo, etc
that was trapped in the gravel in the tank. SHOULD I look for an
ammonia/nitrite spike as a result of losing a large part of the biofilter
and treat the tank as almost newly cycled? I can do significant water
changes without major chemistry changes (beyond ammonia, nitrites, etc). I
can also bring cycled media from other tanks.

I guess the biggest question is how big could this change be? I could and
probably am risking fish's lives, but I feel the benefits outweigh the
risks. The needs of the many outweigh the needs of the few..... or the
one....

---tia

---scott

[Elaine T]

Scott wrote:
> I made a major change to my 55 gallon established (cycled and stocked with
> 15 various fish) tonight, and wonder about potential serious changes to
> water chemistry that I wonder if anyone can answer. The gravel I was using
> in the tank was quite large, around 1/4" in diameter and I noticed that a
> lot of debris was making its way to the bottom of the gravel - IE when I
> vacuumed the gravel I was getting a LOT of crap collecting deep in the
> substrate. This concerned me because I feared anoxic layers developing in
> the deeper layers of gravel and producing potentially toxic compounds.
>
> So... I removed all of my fish - and saved about 25 gallons of the old tank
> water - some in two 10 gallon tanks, and some in 5 gallon buckets. The fish
> were moved to the two 10 gallon tanks, and the filters from 55 gallon tank
> (two penguin 350b filters) were put on each of the 10 gallon tanks to keep
> them running and preserve the biological media in the filters. Then I
> totally changed the substrate in the 55 gallon tank to a more sand like
> substrate. Kind of a trade-off between using very expensive flourite, and
> using a small diameter gravel/sand. Eventually I would plant this tank with
> some low-light plants. The gravel I used is pool filter sand, which claims
> not to be chemically treated. I took the sand and rinsed it in an old
> pillowcase to remove as much debris as possible.
>
> End result now... my fish are ****ed at me and not feeding normally - but
> could be expected from being netted twice in one night. Water is quite
> clear. My big question is - the gravel does support a portion of the
> bio-filtration. I removed a large portion of that bio-filtration, but I must
> have removed a large bio-load on the tank with decomposing food, poo, etc
> that was trapped in the gravel in the tank. SHOULD I look for an
> ammonia/nitrite spike as a result of losing a large part of the biofilter
> and treat the tank as almost newly cycled? I can do significant water
> changes without major chemistry changes (beyond ammonia, nitrites, etc). I
> can also bring cycled media from other tanks.
>
> I guess the biggest question is how big could this change be? I could and
> probably am risking fish's lives, but I feel the benefits outweigh the
> risks. The needs of the many outweigh the needs of the few..... or the
> one....
>
> ---tia
>
> ---scott
>
>
Hard to be sure, but nitrifying bacteria grow very fast and you kept
your filters going. You also greatly reduced the bio-load on the tank
by removing all the mulm from the bottom. My guess from moving my own
fish around at times is that you won't see any ammonia or nitrite. I
think at worst you'll see a mini-cycle with low levels of ammonia and
nitrite, so test for ammonia just in case.

--
Elaine T __
http://eethomp.com/fish.html <'__><
rec.aquaria.* FAQ http://faq.thekrib.com

[Jenn & Drew maillet]

I change my gravel on a regular basis, I get bored easily. My fish don't
seem to mind, and it adds variety. I've never experienced any ammonia
spikes. Just remember to keep the filters up and running, and keeping some
of the "old" water is a nifty trick too.

One thing about the gravel vs. sand though. I found that the junk that gets
its way into the gravel easy enough to syphon out, and it helps keep the
water clear ( hidden junk ). As for sand, thats when you get into a bit of
a tricky spot, because you'd be unable to clean the sand (sticking the
python in and moving things around) as you would gravel, the anerobic
bacteria would be more likely to form.

I have used sand in the past, and I find it a little less attractive solely
for the reason that the junk has no place to go, so it just kinda hangs out
on top of the sand.

Hopefully you'll get something useful out of my ramblings... :)

Jenn




"Scott" <smaxell1{at}hotmail.com> wrote in message
...
>I made a major change to my 55 gallon established (cycled and stocked with
>15 various fish) tonight, and wonder about potential serious changes to
>water chemistry that I wonder if anyone can answer. The gravel I was using
>in the tank was quite large, around 1/4" in diameter and I noticed that a
>lot of debris was making its way to the bottom of the gravel - IE when I
>vacuumed the gravel I was getting a LOT of crap collecting deep in the
>substrate. This concerned me because I feared anoxic layers developing in
>the deeper layers of gravel and producing potentially toxic compounds.
>
> So... I removed all of my fish - and saved about 25 gallons of the old
> tank water - some in two 10 gallon tanks, and some in 5 gallon buckets.
> The fish were moved to the two 10 gallon tanks, and the filters from 55
> gallon tank (two penguin 350b filters) were put on each of the 10 gallon
> tanks to keep them running and preserve the biological media in the
> filters. Then I totally changed the substrate in the 55 gallon tank to a
> more sand like substrate. Kind of a trade-off between using very expensive
> flourite, and using a small diameter gravel/sand. Eventually I would
> plant this tank with some low-light plants. The gravel I used is pool
> filter sand, which claims not to be chemically treated. I took the sand
> and rinsed it in an old pillowcase to remove as much debris as possible.
>
> End result now... my fish are ****ed at me and not feeding normally - but
> could be expected from being netted twice in one night. Water is quite
> clear. My big question is - the gravel does support a portion of the
> bio-filtration. I removed a large portion of that bio-filtration, but I
> must have removed a large bio-load on the tank with decomposing food, poo,
> etc that was trapped in the gravel in the tank. SHOULD I look for an
> ammonia/nitrite spike as a result of losing a large part of the biofilter
> and treat the tank as almost newly cycled? I can do significant water
> changes without major chemistry changes (beyond ammonia, nitrites, etc). I
> can also bring cycled media from other tanks.
>
> I guess the biggest question is how big could this change be? I could and
> probably am risking fish's lives, but I feel the benefits outweigh the
> risks. The needs of the many outweigh the needs of the few..... or the
> one....
>
> ---tia
>
> ---scott
>

[lgb]

In article >,
says...
> One thing about the gravel vs. sand though. I found that the junk that gets
> its way into the gravel easy enough to syphon out, and it helps keep the
> water clear ( hidden junk ). As for sand, thats when you get into a bit of
> a tricky spot, because you'd be unable to clean the sand (sticking the
> python in and moving things around) as you would gravel, the anerobic
> bacteria would be more likely to form.
>
It seems to me that much less junk would penetrate the sand, and what
does would be very small. Yes, it could build up over time, but plants
should use a lot of the nutrients. And how about a nice resident
population of blackworms?

--
BNSF = Build Now, Seep Forever

[JUSTIN BOUCHER]

Okay...
I've seen it several times now and I'm curious...

Some people have mentioned blackworms as a kind of invertebrate cleaner
species for freshwater tanks. I know they''re an excellent source of live
food, but I have not heard of them being used to clean the mulm and junk
within a substrate.

First, is this true? And if it is, what is their diet? I have MTS and am
starting some live plants as well. I do not have a UGF nor anything else
under gravel. (Just rock on acyrlic.)

It's a large deep tank and vacuuming the gravel is a real chore. I don't
expect the use of blackworms to eliminate the need to vacuum, but if they
can help reduce the frequency along with the live plants, that would be
nice.

Thanks,
Justin

"lgb" > wrote in message
...
> In article >,
> says...
> > One thing about the gravel vs. sand though. I found that the junk that
gets
> > its way into the gravel easy enough to syphon out, and it helps keep
the
> > water clear ( hidden junk ). As for sand, thats when you get into a bit
of
> > a tricky spot, because you'd be unable to clean the sand (sticking the
> > python in and moving things around) as you would gravel, the anerobic
> > bacteria would be more likely to form.
> >
> It seems to me that much less junk would penetrate the sand, and what
> does would be very small. Yes, it could build up over time, but plants
> should use a lot of the nutrients. And how about a nice resident
> population of blackworms?
>
> --
> BNSF = Build Now, Seep Forever