[Tex Gal]

I hope your new plant choices work well for you. I will say that if they don't you can still change out your substrate WITHOUT another tank. I just went to Home Depot and got a 33 gallon rubbermaid container and used my tank water and moved my fish over into that. (My thread is 126g at bottom if you want to read the story.) I put my new soil in. I even had to leave my fish in the container for over a month and I only lost 4, 2 ottos (they aren't a hardy fish) and 2 khuli loaches who committed suicide. Since I used ADA AquaSoil and had to wait for it's cycle I couldn't put my fish back in right away. You could do it in a day. Your fish would be fine. Anyway you have a plan B if your new plants don't work.

 

[Tex Gal]

Its a 55g tank with 100lbs substrate Not counting the Crushed Oyster shell total about 115 lbs Substrate. I mean i guess i could change it out BUT then i run into another problem, PH shock to my Fish, they are used to 8.4 Steady, i don't know how well they would fair a sudden Drop to say 7.0 or less.
No cichlids btw this is Mollys,Cory Cats,Guppys,A Placo and a Pictus Catfish and 3 glo light tetras. Not to mention i don't have Sand or Gravel on had, just some Topsoil with Peat moss in it, so it would be a big drop in PH.

And i would be worried about completely killing the Biological Filter. Im not sure my HOB's and Canister Could keep up with the waste until the Bio filter is reestablished.

Not to worry! If you end of having to do this just use the same water as your tank in the tub and then change it over slowly a little a day while your fish are in the tub. The HOB will work fine. I have a 125 and put ALL my fish in a 33g tub. They were in there for weeks! I changed 5gs of water every other day. I also had an air stone in there for them. I had some $40 plecos in there (not to mention added cost of shipping onto that $40). Hopefully you won't have to do it, but if you do take heart! It will be fine!