Replacing substrate for an established tank + rescaping

[Hana288]

Hi, I'm planning on eventually re-scaping my large 130L tank once I save up enough. I'm a poor Uni student so I plan to do a lot of research beforehand.

When I first set up I had all fake plant and over the last year replaced all the fake plants with live ones (also add Fluval plant micronutrients). I also set up a smaller tank for shrimp and live plants using ADA Aqua Soil soil rather than grave. Which has been much more successful with the live plants.

So I wanted to replace the substrate in my big tank with a bottom layer or ADA Aqua soil or something equivalent and a top layer of black gravel.

However, I not sure how best to do the change. Should I leave the fish in or take them out? Do it in section (probably difficult) or all at once?

I Do have a small 40L tank I could place them in for a short time. However, one of the Gourami I have one is a bit of a d##k and will chase the other fist if they get too close.

I also want to keep as much of the established tank's water as possible and when I did the shrimp tank found that there was an ammonium spick that could have been from the soil (filled it with water from my big tank).

If anyone has any idea for my tank or how to best tack replacing my substrate I would love to hear from you.

Fish
- 5 rosy fine tetras
- 2 Dwarf Gourami
- 1 moonlight gourami
- 2 Three spot gourami (One is a d##k)
- 1 pleco

And yes I have found out that the moonlight Three spot gourami is not recommended with the Dwarf Gourami because they may be aggressive. However, I haven't had any trouble with them together apart from one of the three-spot gourami who only chases the others a little bit (sometimes) when they get too close.

 

[ZxC]

It is never recommended to add aqua soil to an established tank because it leaches ammonia, which you seen in your shrimp tank. It also is not really recommended to cap aqua soil (especially gravel), eventually the heavy cap of gravel will work its way down, leaving the aqua soil on top.

 

[jeffruth]

There would be no benefit to keep the tank water. BB grows on decorations, rocks, gravel, filter media etc. Very very little is in the actual water.

 

[ZxC]

There would be no benefit to keep the tank water. BB grows on decorations, rocks, gravel, filter media etc. Very very little is in the actual water.

There is one big benefit to keeping tank water.... Identical parameters before and after the substrate swap will limit stress on the tanks inhabitants... keeping water parameters stable is key in the health of fish/inverts.

 

[Luananeko]

Doing it all at once is probably the only feasible option. I second the mention that you shouldn't cap the soil with gravel as the gravel is going to end up at the bottom sooner rather than later. The second you try to move a plant or plant something new the layers will start mixing.

I've never found a good way to do a substrate swap with the fish still in the tank. Especially when disturbing an established tank's substrate, the process tends to throw up all kinds of gunk you don't want your fish swimming through. Saving the tank water won't help with the ammonia spike that the ADA soil releases, but it can help limiting the stress to your fish, as mentioned by ZxC. You can store the water in 5 gallon water jugs if you have them, or you can grab a cheap brand new large trash can to siphon it into. You'll need a pump to pump it back in the tank if you do that though.

The best way to handle using the ADA soil on an established tank is to pre-cycle the soil. You can find instructions on how to do that here: https://www.theshrimpfarm.com/articles/cycling-aquasoil-amazonia.php
You should be able to cycle it in the small tank you mentioned, or in any fish-safe plastic tub.

Good luck!