Lake Malawi Species • Water Parameters for 120Gal

[DJRansome]

If you are using bottled bacteria, follow instructions on the bottle. Including whether/when to change water.

If you are using ammonia, follow the instructions in the CF Library. Including whether/when to change water.

Daily water changes would be if you add fish and you are in trouble because the toxins are higher than 1ppm.

[KBCoggin]

So should I start the API Quick Start?
Then do a water change daily, how much out should be taken?

I used API Quick Start in my fishless cycle, but I also had two very established sponge filters in the tank so I am not sure how much, if at all, it helped.

Once you add fish you will need to do water changes 1-2 times a day like DJ said. Test the water every morning and evening and see how high your ammonia and nitrites are getting (nitrates won't be a concern yet because of the frequency of water changes that will be needed). If you are getting 0.25ppm on either Ammonia or Nitrite then you need to do a 25% change. If you are getting 0.5ppm then you need to do 50% change. If you are getting any higher then you need to increase the frequency of the changes; potentially 3-4 times a day. I would recommend that you start with 1 breed of fish, and VERY few initial stocking (like Deeda said maybe 6-8 fish). If you go overboard you won't be able to keep up with the water changes and may kill the entire tank. If you decide to do the fish cycle, please please please make sure you can commit to the water changes multiple times a day. Killing the entire tank would be a real bummer on your moral as well as your wallet. Also factor in the cost of water, 50% change on a 120g tank is 60 gallons PER DAY for 6 weeks IF you only needed to do it once a day. This obviously won't be an issue if you are on a well, but if you are on city water it can add up fast.

Although the waiting sucks, dosing with Ammonia is the best way to cycle a tank because you can dose to toxic levels and just leave the tank alone to do its thing without worrying about water changes or killing anything. The cycle happens much faster because there is so much ammonia in the tank for the bacteria to feed off of.