Replacing Substrate

[Pleco]

Any precautions I should take when replacing my substrate? It's in a 40G tank that's been established for about 7 years.

I know there is a ton of bacteria in the substrate so I am tempted to believe I should do this in phases, maybe do half at a time, or take it slower?

I figured someone here has replaced substrate in an established tank and could lend me some advice and experience.

Thanks!

 

[alia258]

I've never replaced substrate before, but here's what I think would work:

1.) take about half of your current substrate and put it in a large enough container (like a low edged square Tupperware, I think that would be best) and remove the rest. (make sure you keep the stuff in the Tupperware wet ) then put the new substrate in and just leave the thing of other gravel on top of it and let the other gravel seed. Remember that the BB will only grow to the point to where it uses up the same amount of bio waste that's produced (so lets say you have ten points of bio waste, then only 5 bacterial would grow because each one would use two points of bio waste {aka ammonia, nitrates, and nitrites} this is only an example and is not a serious scientific thing) so you'll be taking half the BB out so new ones will grow in the new substrate and then when you take the other half out the rest will grow new ones in the rest of the substrate.

2.) have the new substrate sit in a box in the aquarium untill seeded, the larger the amount the better because only a few bacteria will move to it. Then just replace the substrate with the new stuff. Not totally sure that'll work, someone should correct me if I'm wrong.

Be careful because substrate that's sandy will knock up lots of dust and such and decrease visibility for a day or two, but will settle down eventually.

 

[Hobgob]

What are you changing it to? I redid the substrate in one of my 35s a couple months ago and had a thread for it. There could be some good ideas in it. You can take some of your substrate and put it into a pantyhose to help seed your new substrate. I removed my fish and took all the water out soni could completely clean under my substrate. Now I know everyone says a bunch of bb lives in the substrate but unless you have a ugf or never vacuum the gravel I disagree. Bb likes to live where there is an abundance if nitrogen present like in the filter. Also I didn't seed my new substrate and had no mini cycle at all. I also had a ugf at the time which was why I was removing my substrate.

 

[Pleco]

What are you changing it to? I redid the substrate in one of my 35s a couple months ago and had a thread for it. There could be some good ideas in it. You can take some of your substrate and put it into a pantyhose to help seed your new substrate. I removed my fish and took all the water out soni could completely clean under my substrate. Now I know everyone says a bunch of bb lives in the substrate but unless you have a ugf or never vacuum the gravel I disagree. Bb likes to live where there is an abundance if nitrogen present like in the filter. Also I didn't seed my new substrate and had no mini cycle at all. I also had a ugf at the time which was why I was removing my substrate.

Over 7 years the blue gravel has slowly turned colors and now looks rather bad, we were thinking of going to a small/medium mix natural colored pebble substrate since we basically have redone everything else in the tank. To add to this most the redesign was because we have/had a pretty bad BBA outbreak, some of that BBA is stuck to substrate. Removing the decorations and plants removed most of it, as well as the filter/heater and scrubbing off the little bit that attached itself to the silicone but I really don't think it would be possible to get it all out of the substrate and would rather not risk having yet another bloom of it.

It had a Marineland Eclipse 3 filter/light hood on it, the filter was abysmal. I replaced it with a Filstar XP3, replaced the heater, decorations, plants etc. Now we would like to do the substrate. All of this has been fairly recent.

It's not sand so im not too worried about that, and the tank is not planted nor will it ever be planted. I deep gravel vac often so I doubt there is much under the substrate but you never know until you pull it up right?

I was thinking to use a media bag and instead of putting carbon in it put some substrate and place it in the bio basket in my filter. Not sure if that would be good or not though.

I have no other place to put the fish and worry replacing the substrate will send it through a cycle and either make them sick or worse kill them.