Changing Substrate

[superpeytonm]

I've had my 75g for nearly three years now, and I've decided I'm tired of the multi-colored gravel. It's too deep, and it's an eyesore. Is there a way to change my substrate out without harming the fish or having a mini cycle? How should I go about doing this?

 

[Caliban07]

Hi

I think you will have to expect a mini cycle at least. The substrate is home to a large portion of microorganisms and disturbing the substrate sufficiently will have biological and water chemistry effects. The severity of which will also depend on the type of substrate and the amount of organic matter that resides in there etc.

Best thing to do is remove the fish.

Remove the substrate

Add new substrate

Refill with conditioned and temperature suitable water.

Add fish

Monitor levels of ammonia, nitrite etc but also keep a close eye on the fish. It may also be a good idea to siphon a good quantity of the old water out and mix that with the new source water to reduce shock levels to inhabitants.

 

[TMaier]

Totally agree with Caliban. I did a tank move from a 10 to a 20 all new substrate and no casualties.

 

[Toad]

When I've changed substrate I vacumn the heck out of it first so all that mung isn't going into the water as much, then net the old stuff out, replace with well rinsed new stuff. I didn't move the fish because I had so many small fish, so they went to whatever opposite side of the tank I was workinh on.

 

[dalto]

Changing substrate out is a pain in a big-ish tank. I have found trying to do it with fish in the tank is more trouble than it is worth and exceptionally stressful for the fish. I usually drain the tank altogether while vacuuming as much as possible. Scoop as much as the substrate out as I can but then you are left with a bunch of dregs that have to be removed. I have tried everything from scrapers to cardboard to dustpans to remove it. It is just time consuming.

As for your mini-cycle, how bad it will be will largely depends on what kind of filtration you are using and the stucture of your water flow.

• With an HOB should try to disturb the HOB as little as possible. Don't use the opportunity to replace the cartridge or clean the media. You can do that at a later date.
• With a UGF you are basically screwed in this situation. About the best thing you can do is temporarily put a bunch of the gravel in fine mesh bags and drop them around the tank.
• The canister situation is simple. Don't touch it. Shut the flow off, switch gravel, refill the tank, turn the canister back on.
• With a sponge filter put some of the original tank water in a bucket/container and move the sponge filter into it. Don't squeeze it out.

 

[superpeytonm]

I appreciate all the answers everyone. I won't be changing the substrate for a little while, as getting enough of the kind I want is costly. But all the responses have greatly helped me plan my course of action for later in the year. Thank you!