DARB

I don’t know where to post this I hope I'm in the right area. Well I have a 55gal cichlid tank and I want to up grade the tank to ether a 75 or 90. The problem is Its has to go in the same spot of the 55gal. The 55gal has been established for over a year the ? is would it be safe to tear down the 55 move in the 75/90 in its place then add the old substrate and water from the exciting 55 and all the same media and not have to worried about a cycle?

Amanda

Is MAY throw you into a mini-cycle, but you should be alright is everything is trasnferred in a timely manner.

pepetj

If possible I aim for bigger tanks so I say go 90!. Make sure your stand can handle the added weight.

This is what I know of our delicate and beloved beneficial bacteria: If you let 4 hours or more pass since you stop the filter in the old tank until you re-start it in the new one you are likely starting from zero.

The shorter it takes for you to complete the upgrade, the better things will go.

My suggestions: (feel free to modify them)
1) If possible, let your fish fasten for a day before doing this (they seem to manage stress better when not digesting food). Then collect all the fish in a bucket or smaller tank while keeping the old tank running. Use water collected from the old tank.

2) Tansfer your Whisper power filter in the bucket/small tank and keep it running there. Be creative, I had to tilt forward a bit a HOB so it could work in a bucket. As long as it runs its OK, it doesn't have to look pretty.

3) empty your old tank, if possible save 10 or 20gals for adding back into the new tank. This is not entirely needed but will make acclimation to the new tank easier.

4) remove all the substrate and decor and place it as safely as possible (I used big plastic bags placed on top of old newspaper to minimize the cleaning chaos afterward), if you keep plants dump them with the fish. This is a great opportunity to hunt down unwanted solid waste, such as broken rubber bands, loose suction cups, a small torn piece the seal of fish food from a container (orange color strip from Tetra Nature's Delica anyone?) that unnoticed went down there, you might find a lost earring or worst, a copper coin (happened to me once).

5) place your new, previously cleaned tank. Check it is leveled. Apply some pressure around to see it is well fit in the stand. Check for the space to the wall if you need adjust its positioning.

6) Bring all the substrate back in, distribute the best you can, you will correct later. Place a long plate in the middle and place the water hose so it falls in it, add enough water treatment (I would use Tetra Aqua Safe or Seachem's Prime or alike) and let the waterin. Some spill can happen but won't disturb the substrate much. Fill the tank to 2/3. If you saved old water, add the 10 or 20gals now. If you have an airpump consider using it in the tank for now.

7) Place decor and plants, give the suspended solids in the tank 15-30 minutes to settle in. It will likely still look cloudy (depends on substrate) but take the filter in (don't clean the filter media!). Refill the tank and take your time acclimating your fish back into the tank.

I've done something similar but without replacing the tank, as I have upgraded substrate. In my substrate upgrading, I have spent from one to one a half hour to do this in a 45 and 145gal tank, respectively.

Pepe
Santo Domingo

DARB

Thanks that step by step makes should make the transition a hole lot easier.

Angela_96

For cichlids a 90g !! If I had the floor support for a 90g I would have one they are an awesome cichlid sized tank!

aquarist48

I vote for the 90g!!! It's been my experience, the larger the tank the easier it is to maintain. 15 gallons may not sound like much of a difference but it is. Have fun shopping and keep us posted.

harpua2002

This has not been my experience at all. I've moved multiple tanks and fish to different states a couple of times. The first time was about 100 mile move, the second time was 440 miles. The second time, I had all the fish bagged and filters off for over 12 hours. None of the tanks re-cycled and all the fish survived. I've done many tank upgrades as well and had no issues there either. Based on many personal experiences, I've drawn the conclusion that both fish and our biological filters are a lot more resilient than they often get credit for.

wakingupnow

You have to make sure that what ever it is that your 75 or 90 gal will go on, is large enough for the entirety of the bottom of the tank to be covered and of course for it to be sturdy enough.

A gallon of water weighs about 8.35 pounds so a 75 gallon tank filled with water (without gravel or other things) is 626.25 pounds. The 90 gallon with just water in it would be 751.5 pounds so you really have to be 100% sure that where this tank goes is going to have an extremely sturdy resting place.

I think it's a very good idea to just transfer all the equipment and decor from your 55 to the 75 or 90, but you may need to buy more gravel and decorations to fill in the spaces. One thing you must to is make sure to keep all the decorations, gravel and filter media in tank water so the Beneficial Bacteria does not die on you. The quicker transferal, the better.

I hope this helped. :-) Good Luck!