Question: Replacing substrate and adding a 3D backing to a cycled tank

[dazkeirle]

Hi all,

I've just purchased a new tank, full of Algea and gravel and water, it's safe to say it's cycled.

There are also large rocks, and wood inside the tank. Living inside are several fish right now.

The tank will be used for my Axolotl.

So far I have wiped away the real build ups of Algea and water parameters are still good.

What I need to do I'd remove all of the gravel and replace with sand, but I also have some nice Juwel 3D backing to add to the rear inside of the tank, this needs to be siliconed in.

What I need to know is, If I removed the fish temporarily and some of the "dirty" water, could I do the backing and substrate in the empty tank and then refill with the dirty water and dirty rocks / plants and still have a well cycled tank or will this nuke all the bacteria and put me back to square one because it was emptied of water?

I do plan to remove the gravel bit by bit daily, with all the fish still in the tank, to allow the tank to adjust as I remove the filthy substrate and get it to a position where I can begin adding sand. Its the adding of the background that's causing me a headache as tank needs to be emptied

Any expert opinion would be brilliant.

 

[Mac Myers]

My 15.3 cents. Far from expert.
Silicone is toxic until cured. If the background "fits" well... completely blocking all sides and bottom then I'd install it with suction cups. If not ... then adding some silicone to the "short" areas and letting it cure before putting it in the tank might work.
Emptying the tank for 24 or so hours to cure silicone will kill off the beneficial bacteria. Some will remain on the wood, plants etc.... but not mush in the water. Might kill the bacteria in the filter too depending on what happens to it during the curing. I work on getting the rocks out first.
How well does the background fit?

 

[dazkeirle]

My 15.3 cents. Far from expert.
Silicone is toxic until cured. If the background "fits" well... completely blocking all sides and bottom then I'd install it with suction cups. If not ... then adding some silicone to the "short" areas and letting it cure before putting it in the tank might work.
Emptying the tank for 24 or so hours to cure silicone will kill off the beneficial bacteria. Some will remain on the wood, plants etc.... but not mush in the water. Might kill the bacteria in the filter too depending on what happens to it during the curing. I work on getting the rocks out first.

That's what I'd assumed, It's gonna be best to do everything very gradually especially as I need to remove all substrate, rocks are easily removed too, they're just plonked in there.

To be honest I hadn't considered suction cups, that's a great idea and means I can install with all the water still intact.

The background is the Juwel 3D bark effect, which you cut to size and is made of a safe polystyrene. It goes inside the tank and will be 2/3 pieces dovetailed together and i have plenty so that's not an issue.

Maybe my plan of attack is now:keep all water inside of tank

• Remove gravel substrate
• temporarily remove rocks and wood (store in bucket of dirty water)
• measure and prepare background for installation
• affix suction cups
• submerge background into tank and stick to back
• add new sand substrate
• replace rocks and wood

This way filter and all ornaments stay wet with dirty water. and more importantly the fish don't have to be removed.

 

[Mac Myers]

That sounds good. That way the only "new" stuff will be the background and the sand. :happy:

Let us know how it goes.