I think I'm done cycling

My tank has been going for 5 weeks now and my parameters are:

Ammonia 0
PH 8.4
Nitrites 0
Nitrates 40 ppm

These parameters have been holding steady for about 3 days now and prior to that my nitrates were at 20 ppm a few days. They are climbing so is it fair to assume that the cycle is done and it is time for that first water change? To me it seems kind of fast but I've read that it can happen this fast.

 

At least 3 weeks to go...

 

So I should wait a little longer before I change the water?

I'm getting a little anxious to change the water because the water level has evaporated to a point that causes the return water from the filter to be really loud. It sounds like I have a water fall in my living room ;D. What about the nitrates? If these label continue to rise could this possibly kill my damsels?

 

Do another water change to get the nitrates down. Nitrates will cause algae to grown, ver high nitrates will cause fish to die. If you run a reef, you need to have 0ppm on all ammonia cycled params, FOWLR is more forgiving on nitrates, <40ppm. If your nitrates rose from 20 to 40ppm, you still have about a month to go to get them down to 0 (depending on your tank size of course), as PL stated.

 

If your water is evaporating then you need to replace that with RO/DI water not with new saltwater. The salt doesn't evaporate only the water does.

 

I'm working with a 29 gallon FOWLR. As of right now I have no plans to move to a reef system. I will stop by the LFS tonight on my way home get some fresh RO water to top the tank off. I am starting to notice that the sand bed has some brown spots starting form which I'm sure is algae loving the new higher nitrate levels.

 

You have a good cleaning crew in there?

 

^ No not yet. I thought it was best to wait until the tank has finished cycling.

When should I start skimming?

 

Cycle is eternal. Having said that, once your ammonia/nitrites are down to zero and nitrates are starting to fall (say below 20) would be a fine time to add clean up crew. I didn't wait until my nitrates were zero, just until they started to drop.

You can start skimming whenever you want. From the wide range of opinions on exactly when to start, it seems to have some leeway. It will probably slow your cycle down. But nothing wrong with going slow. I haven't yet added my skimmer.

 

We will see how long that lasts!! I give it 2 months! The reef is the best part of a tank by the way;D You will get sucked in soon!

As for the skimmer I still don't have one after over 10 months. With only 2 fish it hasn't been a problem, my nitrates stay low with a good cleanup crew. So right now you don't need to be in a hurry to turn one on IMO, just my 2 penny's, someone else will tell you to turn it on yesterday!