I have a 500 L aquarium I would like to fill with saltwater and eventually fish. I have an 80 L tank starting to cycle now on the 3rd week, containing about 2 kg of live rock.

I plan to partially fill the 500 L tank with the contents, filter and power head of the 80 L tank, and over the following weeks, put in newly purchased live rock, more coral substrate, and more water. Week by week, I plan to add more water.

Will this plan have a chance at success, and if not how should I modify it? I don't want to spend all my money at once!

  • just to make sure, does you aquarium have a deep sand bed? Commented Oct 23, 2013 at 12:11
  • Thanks Josh. The sand bed of the 80 L tank is about 2.5 cm deep on average. The 500 L tank has the rest of the bag and no water, so barely covers the bottom. I'll buy another bag before the transfer then. Ammonia is 0.25 ppm, Nitrite 0 ppm, Nitrate 10 or 20 ppm. The hang on protein skimmer will sit on a 15 L empty aquarium I'll put inside the 500 L to be at the right water level for the time.
    – user214
    Commented Oct 23, 2013 at 21:06

1 Answer 1


This answer assumes you have a deep sand bed (photos) in your aquarium.

When you cycle your aquarium, it means all your micro-fauna are being built. The lower part of the sand bed should already have some anaerobic bacteria living in it. I'm not sure that it's already built up in 3 weeks, but surely it is on its way.

When you move items to a new aquarium, probably you'll lose some of your bacteria. To prevent having to cycle from the beginning, you could move all that sand very carefully, keeping the bottom sand at the bottom and the superficial sand at the surface. This way you can preserve the majority of your bacteria. Over time, they will recompose, without taking an entire cycling period.

This can be a successful process, but it'll add 1-2 more weeks to the entire process.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.