The Puffer Forum

Recently, my tank has finally cycled. (a-0 ni-0 nitrate 20) How much water should I change and how often should I change it in my GSP tank without killing the bacteria?

Your bacteria lives in your filter, substrate, and decor..so you can change as much water as you want...but I do about 20-30% weekly..

Edit...the amount of fish in the tank and the tank size does play a big part in how much water you should change per week..

As long as you declorinate you are fine!

thanks!

No problem..if you have anymore questions please ask! and congrats on the new tank!

Hi, questions:

Using Bio-Spira (the "stable non-refrigerated" vial intended for 30 gallons), how long does it take for a brackish tank to cycle?
the bottle of bio-spira says the tank is "instantly ready for fish", and we let it sit for about 10 hours before introducing our GSP, but people at the fish stores and online said one should let it develop over days or even weeks. I'm paranoid the bio-filter has not established, or if it has then i'm afraid that raising the SG (but not more than .002 per week) may kill what has grown.

Can a tank be cycled with a low SG (1.003), or does it need to cycle in fresh water?

I believe Bio-Spira is meant for SW tanks, not BW or FW.

am i right in thinking there is no way to know for sure that a bio-filter has established, other than monitoring the water conditions (nitrate/nitrite)?

Once fish are in, you are correct.

Before fish are added you could have added ammonia and monitored it's conversion to nitrite and that in turn to nitrate. That is effectively a short-circuited "fishless" cycling technique.

Otherwise, leaving the bugs without an energy source for days to weeks is called starving them to death - more bad info from fish stores.

HTH

Bugs = bacteria.