How many water changes?

[Fish noob]

I just finished cycling my 60g cube after 5 weeks. Ammonia and trites are at 0, but nitrates are off the chart.

I did a 25g water change yesterday and trates were still sky high, I did another 25g water change this morning and nothing changed. I just did ANOTHER 20g change and the trites are still super high.


How many water changes must I do? I would do more than 25g at a time, but am getting the water from the LFS and I only have 5 buckets.

[shifty51008]

have you chacked the water from the fish store for nitrates? tried a diffrent test kit? by now you should at least see a drop in nitrates

[Fish noob]

Yes, I tested the LFS water before using it. I' using API test kits and have never had a problem with them. Nitrates had been around 20 during the cycle, then when the nitrites finally went to zero, the nitrates spikes and I can't get them to drop

[Fish noob]

Are all of these numerous water changes going to mess things up? I hate to have spent the last 5 weeks cycling just to have to start over because I did too many water changes?

Is there any other way to lower nitrates other than changing the water?

[SushiGirl]

Water changes are not going to make your cycle start over, they're the fastest way to reduce nitrates, especially after the cycle. The nitrifying bacteria are in the live rock and sand, not really in the water.

[dunc101]

Water changes are not going to make your cycle start over, they're the fastest way to reduce nitrates, especially after the cycle. The nitrifying bacteria are in the live rock and sand, not really in the water.

Exactly. I would do a 95% water change, match the water temp and salinity.... and you should be good. Everything you did during the cycle exists on your rock, and not in the water column.

If you think about it, it makes sense
Example in 60 gallon system:
1.) Nitrates = 100 ppm
2.) After 20 gallon wc, nitrates = 66 ppm (remove 33% of the nitrates)
3.) After another 25 gallon wc, nitrates = 38.5 ppm.


If you did a 95% water change and you had 100 ppm initially, you will be down to 5 ppm nitrates.