Fish care & cycling during a tank "re-build"
 

After 10+ years of maintaining a 40g heavily planted tank, I'm switching it over to a driftwood and rock-only setup for less maintenance. I don't use activated charcoal in my 75g power filter since I don't want to remove nutrients.so it only contains a sponge to collect debris. Does the following plan sound correct?

1) Move fish (10 pristilla tetras & 3 platys) to 29g. Will use the water from 40g. Use smaller power filter w/charcoal and put established tank's 2 sponges in temp tank. No gravel, but will toss in some old plants to give the fish cover.

2)Clean/scrub out old tank. Add new gravel, cleaned driftwood, rocks, etc. Fill with treated tapwater and turn on heater and big power filter now with new charcoal/sponge cartridge. Put 1 of established tank's sponges that's been in the 20g back it into the 40g.

Have I forgotten anything? How many days do you think this transition process will take? I will be doing ammonia, nitrite and nitrate tests on the new tank and maybe after a couple days of filling the new tank I can add 1 of the platys to it if readings are at 0, and keep testing for a week? Then add 2 more fish and test for a few days, etc? Is a plan for 2 weeks to do the full fish transfer of 13 fish realistic? Maybe after a month remove the old filter sponge and just continue with the charcoal filter cartridges and weekly 20% water changes.

Can it be this straight forward or am I forgetting something? It's been so long since I've set up a new tank!! Thanks in advance for your thoughts!1

good plan, im sure you know the following but ill say anyway...
remember to choose rocks carefully and keep an eye on pH.
be careful what you use to scub out the tank and clean it as residues can be left behind and with no plants to absorb latent toxins they can be detrimental to the fish.
once the new tank is up and running take the filter from the temporary tank and put it into the new tank for additional filtration, this will benefit the fish and allow for something closer to gin clear water!

Good plan though!

Thanks for reviewing my plan! Yes, will be cleaning out the old tank with a vinegar & water solution - no chemicals or soaps. Will do the acid test on rocks and will be boiling driftwood branches I've collected. I hadn't thought of adding the 30g power filter in combination with the bigger one on the "new" tank once all the fish are moved to it, but I'm sure that SUPER filtration couldn't hurt for a while. Thanks!

How did you acid test the rocks? I just got a bunch of river rock from the local landscaper. I sprayed the heck out of them with the hose to get all the lose dirt/dust off and they appear to be clean... Good to go or more?

Testing your rocks with a couple drops of muriatic acid will either make it fizz or do nothing. If your rock fizzes = not aquarium safe. If the drops of acid get no reaction then rinse/scrub off acid and add to your tank!

And is muriatic acid easy to find??

You can use the Regent #2 from the API nitrate test kit, it is a strong acid. Some also suggest vinegar, which if it fizzes would certainly indicate calcareous rock; but vinegar is a fairly weak acid, so if it does not fizz, there is still the possibility the rock might be calcareous. I would start with the vinegar if you have some.

Calcareous rock is fine in hardwater fish aquaria, like livebearers and rift lake cichlids. So for these setups, it doesn't matter. But in softwater fish aquaria you do not normally want rocks increasing the hardness (depends upon the initial hardness of the source water and tank).

Byron.